Chest, shoulder & neck pain???

Ok - I will try to give as much detail as I can without taking up your whole day!

On Wednesday night, I watched a movie while lying on the floor, with a pillow, and lying on my right side. When I got UP from the floor - I had a very sudden & very painful stabbing pain in my LEFT shoulder area. It went down the left arm almost to the elbow. At first, I attributed it to lying on the floor Went to bed & woke up about 3 times during the night in EXCRUTIATING pain - not only in my neck/shoulder/arm - but in my left sided chest (including about half of my breast & just below it. I went to the ER Thursday & they said it was probably a muscle strain, with maybe a pinched nerve & gave me pain meds & a muscle relaxer. These help with the chest pain (a little) - but nothing for the neck area. I called my primary Doc & he said probably nerve, but nothing they could do for it anyway (I dont have insurance).

My question is: could this be something else that MAY be emergent?? Please help...