Need Help! Pitching Shoulder Pain!

Hey guys I need some advice,

About a year ago I started feeling a “dead” arm, luckily it was toward the end of the season so I figured it was just the amount of innings that I had thrown. So after the season ended I took about a month or two off before I did any arm related exercises. After a month and a half I joined a local gym with the goal to gain weight and possibly build velocity on my fastball. About 3 or four months after the season had ended I began throwing, just light stuff on flat ground, the arm felt great. So after a couple of weeks of getting my arm strength back up, I decided to throw a short bullpen. I began feeling the same kind of pain again, this time I felt it more in the external rotation just before I drive forward with my front leg. I immeadiatly stopped and decided I needed to see a doctor. I got x-rays initially and they came back negative, the doctor thought my bursac was inflammed. He told me to take a month off and stretch it out everyday and he said it should loosen itself up. About a month later i tried throwing again and the same pain occured, my velocity was down and It hurt to snap my breaking ball off as I normally would. A few weeks later I went in for an MRI, I feared it would be a tear in my labrum or worse possibly a rotator cuff tear. But yet again the MRI came back negative! I was getting frustrated. So I went to physical therapy, the physical therapist told me not to throw for about 4 weeks. I did all the exercises they gave me and never missed an appointment. At around 5 weeks after starting physical therapy I started playing cach again, with no pain unless I tried to throw hard. And since i’ve spent my whole life pitching I’m getting extremely frustrated and upset because apparently there is nothing wrong with my shoulder but I definetly feel the pain.

So basically I’m asking for help, and or any kind of hope. Any information or ideas for me to do would be greatly appreciated. Thank you!