Can anyone help me identify this? (Injury)

[ajdonutz]

Ok so i THINK it started when i was doing decline skullcrushers the other day.. i went down and had some pain in my rear delt/tri, i did a few reps but it was hurting so i didnt do any more sets and called it a day. Well the next couple days the area hurt when moving my arm in certain positions, hard to explain them as they are awkward positions. But i get to back day, and i cant support heavy deads due to it hurting andbeing weak. Barbell rows i did without much inconvenience, dumbbell rows were kind of painful but i got through them, however close grip pull ups and lat pull downs and any vertical pulling motion was a complete no go. No strength and painful. When i push on it there is a spot in the rear delt that is kind of tender. It can cause pain in my rear delt and a little through ny side delt and also some in the back of my arm/tricep. I am able to do rotator cuff exercises with dumbbells and rotating arms and what not, its just the vertical pulling i wasnt avle to do... some other exercises can cause slight pain, but any thing with my arm overhead and attempting to pull is a no go... which is really depressing me because my lats are something i have really started focusing on and i want to bring them up...

Any tips or suggestions? Anyone know what the culprit is? Rotator? Any quick rehab?