What Causes Soreness And Pain In One Spot On The Shoulder Blade?

Hello.. I have had this problem for about 4 years now.. The first doctor i went to (about 3 years ago) said that it was just a small muscle tear and would heal on its own after a few weeks.. But i now still have the same problem.. The best was i can describe it is a sharp, precise stabbing, burning, stinging pain in one particular spot on my right shoulder blade, in the muscle just on the side of my shoulder blade closest to my spine.. The very first time i felt this pain was when i was 14 or 15, and i was just standing up doing nothing (literally) i was in cadets and we had to stand at attention for 15 minutes or so.. i first felt the distinct sharp pain then... i am now 19 and i have the very same problem only the skin ontop of the area is now numn, yet the muscle beneath is still incredibly sore and painful.. I am now at uni and use a computer pretty much every day, and every single time i sit down to type, i get the same pain and it gets worse and worse until i have to go and lie on my back to make the pain go away... I have been to 2 different doctors and neither of them could help me.. This pain in my shoulder is really affecting my life.. I have tried to research what this could be myself, but all i could think of was a pinched nerve (especially due to the numbness in my skin) but the pain doesn't radiate down my back or arm or anything.. it stays in the same area and sort of creeps around that one place.. I don't know what more i can do.. I hope you can help!