Shoulder/trap/neck/collarbone pain after workout. What is wrong?

[redmchalo]

The day of my workout, I noticed that my left shoulder was feeling a little odd when I woke up that morning because I slept on it awkwardly. I had to do chest and upper back (rear delts and traps). My first exercise was a flat barbell chest press with good form (shoulders tucked back, slight arch in back, bringing bar down to nipples and not locking out at the top) and I had no pain. But, when I moved onto the incline barbell chest press, things got interesting. I was running late that day and I only had 20 minutes to workout before the gym closed and I had to move immediately to my 8 rep max on those inclines without warming up to them. That is when my left shoulder/trapezius muscle and the side of my neck hurt like hell. I worked through the pain somehow, thinking it would go away. Then I moved onto barbell shrugs and my shoulder, trap, the side of neck and left side of collarbone hurt like hell-didn't get through 1 set because of the pain. There was even a dull pain in my left shoulder blade. I moved onto the rear delt dumbbell raises and the exact same muscles hurt. Shoulder/trap/neck/collarbone all hurt when I raise my arm overhead or laterally. I can still reach behind my back with no problem though. What is wrong? I am currently exercising my rotator cuff, no pain while doing the exercises-"innies and outies" but they are not helping my issue. I tried doing back (barbell and tbar rows) today and I couldn't because of the pain.