Shoulder Injury

Hi, I had a fight (actually I was more attacked) about 2 weeks ago and I ended up on the floor. I hurt my ribs which I already posted a question for but I also had a pain on my right shoulder (probably from falling). This pain was not intense so I was not much worried about it. But now, I still have reduced mobility of my shoulder. It doesn't hurt all the time but only if I put my hand behind my head or extend my arm to the side and backwards. The pain is not intense but it's intense enough to not allow me to do any weights and I have problem when I am sleeping and If I try to put my arm behind my head or extend my arm to the side and slightly backwards. Is this just muscle damage which will go away or did I hurt my joints? The pain is less than it was 1 week ago.

Many thanks