If your arm is bothering you enough that you’re posting on websites asking people to tell if you’re injured or not you should probably get it looked at. Nobody can diagnose an injury based off of descriptions given on the internet you need to see someone who actually knows how to test your arm so you can get an accurate diagnoses and hopefully minimize the amount of damage you’ve done so you don’t ruin your entire career.
Just a friendly reminder. 
I agree. You should see a doctor and if need be ask him to refer you to an orthopedic specialist, preferably one with expertise in sports injuries. The sooner you take care of that, the better you’ll be when you return to action on the mound.
After the 1951 World Series, in which Ed Lopat had won both games he had pitched, he suddenly could not lift his left arm (the weather might have been a factor; it was cold and damp all through the Series). The doctors could not figure out what was wrong with him, and for the first part of the 1952 season he was on the shelf, which he didn’t like at all because what he wanted to do was get out there and pitch! But one day he remembered an orthopedic surgeon in Chicago, a guy he had known in his White Sox days, and he flew out to see him. This doctor examined Lopat and told him that he had tendonitis in his left shoulder, and then he prescribed a treatment which we might call bizarre these days—a series of ten X-rays, which is not used any more. But this worked, and when Lopat came off the DL he was pitching better than ever; from that point till the end of the 1954 season he ran up a record of 33-8, and the 1953 season found him with a 16-4, .800 record and a league-leading ERA of 2.42.
So, if your arm is really bothering you, see a doctor and take care of the problem! 
No doctor posts on LTP. ZW is completely correct…
[size=18]ZITA YOU HAVE A PM!!![/size]
I personally think this section is great to talk more about injury prevention and just about injuries in general instead of trying to provide a diagnosis for someone.
i have no idea what i did but ever since after one game approx a month and a half ago, i feel pain and a pulling sensation with each throw. the feeling is almost in my back, but not quite… it feels as though its underneath my shoulder blade. not vertically underneath, but horizontally. any hellppp?