what did I do to my shoulder?

I swam Wednesday night, and didn't notice anything wrong. Yesterday I woke up and don't remember noticing anything, then after I was at work awhile I noticed that I had difficulty putting on my jacket. It hurts my left shoulder. In the past, all my shoulder pain was a bursitis (spelling?) issue, and this is very different. Basically it is stiff/tender to lift from my side or to reach behind or forware. The pain seems to be at the top of my shoulder and straight down the arm. I know there are lots of folks with shoulder issues, so I'm wondering how I figure out what I've done. Thanks. ACK. I had that and my PT said it was RC. Not neccessarily severe but maybe a little tender. Get a professional opinion though. Ice for pain and inflammation in the meantime--my opinion.

I swam Wednesday night, and didn't notice anything wrong. Yesterday I woke up and don't remember noticing anything, then after I was at work awhile I noticed that I had difficulty putting on my jacket. It hurts my left shoulder. In the past, all my shoulder pain was a bursitis (spelling?) issue, and this is very different. Basically it is stiff/tender to lift from my side or to reach behind or forware. The pain seems to be at the top of my shoulder and straight down the arm. I know there are lots of folks with shoulder issues, so I'm wondering how I figure out what I've done. Thanks. ACK. I had that and my PT said it was RC. Not neccessarily severe but maybe a little tender. Get a professional opinion though. Ice for pain and inflammation in the meantime--my opinion.