First, I am not a doctor! Just my advice to you from experience with my son.
Edema is swelling, which in your case is said to be mild and mid muscle in location. The lack of hematoma is positive, meaning no rupture in muscle. Both of these are good, as far as your situation is concerned.
Taking multiple MRI’s without a contrast is a mistake. Why the MRI/contrast is not done first for a baseball player is unknown to me (cost??), but after one MRI is taken and the condition persists, it is my opinion if another MRI is requested the contrast is needed in order to determine if tiny tears in ligaments and elbow joint tissue exist that won’t show up without it.
Now, like many young kids, you want velocity at all costs. So, you mentioned you started a velocity throwing program. Well, I’d bet dollars to doughnuts the revered throwing program caused the problem. So, in my opinion, what you need is rest and rehab. The throwing program may, or may not, be a a good one. And most likely, you weren’t physically ready to start the program no matter how much you think you train (See below). The dirty little secret is that anyone who starts a Velocity Throwing program is at risk of increased injury, and it can result in serious injury.
Not all rehab/PT is the same! I started out with a terrible one with my son, made a switch, and whoa!, what a difference. Not all doctors are the same. I found a terrific Shoulder/arm surgeon, and the advice/information made all the difference.
You MOST LIKELY DO NOT have anything serious yet, but trouble could arise because you almost assuredly have a muscle imbalance (Training Routine?). Improper muscle development can even make you think you have a nerve or ligament damage because of how the nerves and muscles converge around the elbow. This can result in you describing UCL pain when you actually don’t have an issue with the ligament, but have an issue with the ulna nerve instead, and that can be cause by muscle imbalance. If the pain was structural (meaning joint specific), the pain and discomfort would occur immediately and progress with each throw. Your strength training needs to be reviewed, perhaps certified. A good strength and conditioning coach should be consulted. Maybe your Highs School has one, and also a PT as well. It is my opinion you arm is taking the brunt of the stress when throwing. You lack good shoulder and rotator cuff development. Perhaps your front shoulder is much more trained than your back muscles/back shoulder muscles. START BAND TRAINING IMMEDIATELY to help the rotator cuff.
You’re 16, so I’m sure you train the Bi’s hard. This is not allowing your muscles to heal. The fastest way to get stronger is to stop working out for a week or so. Why? Because your muscles will heal fully. Then go back to to work at getting stronger again. Instead of 5 days a week working out, cut back to 4 days and allow at least a 2 day break in between which allows you more consecutive recovery time. You simply can’t work out to tear down muscle like a body builder and expect to throw max out without causing some problems. If you overwork the same muscles day in and day out, you are causing your own problem. The Biceps and Triceps are the type of muscles where this can happen. Remember this: you train so you can be prepared to throw max out all game. Performing when your muscles are in a compromised state is foolish.
Training advice given that baseballis about to start in March: Give yourself 2 weeks of doing NO arm specific training. DON’T Throw! TRAIN: A good training program will hit the arms, but not directly. The goal is to heal, and working out will enhance blood flow to the arms and allowing to keep your arm strength. You want to heal. Don’t lift anything like you would do a bicep curl. That’s easier said than done! After 2 weeks, start throwing. Use bands to work the rotator cuff muscles before and after throwing. This will help you to arm up and cool down.
DO NOT THROW USING A PITCHER MOTION!
This is what worked for my son, I hope it works for you. My son threw the same velocity as you at your age!
Week 1: Start throwing at 60- 75 percent. Use your body, full easy throws. just don’t strong arm it. throw as prescribed moving from 25 throws to 60 throws at about 60-75 feet tops. Throw everyday if no pain. Increase throw count about 6 per day. Don’t overthrow, in effort, or throw count. Most likely you’ll be at about 75% because it’s hard t throttle it back…We want a progression in throw count which acts as a load that slightly increases as the week goes on.
We are building up as you go along: no need to rush it.
Week 2: If you are at 60 throws after week 1, just having a fun catch with no pain, step it up. Go to 80-85%, starting at 20 throws, working to 60 by end of week. If there is pain at any time while throwing, you’ll have to assess as to how severe and how it feels compared to what you experience now. If the pain comes back but much lighter, than I would say you have confirmation that the muscles aren’t yet sufficiently healed. But, you are on the right rack.
Week 3: If all is good and no pain, the next step is to start throwing as you feel comfortable. If there is pain at any time while throwing, reassess.
If the pain is gone, and you feel like you can throw as you would want to, the only thing to do
is try and do it. Start with increasing distance as in long toss to increase the effort. Then do a blend of long toss and hard throwing as part of your routine. Then, build in flat ground pitching before mound pitching. It’s going to TAKE TIME. The only way to get back to throwing like you want is to convince yourself that the proper training and arm preparation solved your problem. Time will tell if you can put this out of your mind or not.
Time is your friend, but can be your worst enemy if you rush. This time of year is hard to get the rest you need, but you have to grow up and commit. Talk to people you can trust. Be honest with yourself. You are the only one who can communicate what is going on