Shoulder Pain

I occasionally have a deep aching pain in my right shoulder (pretty sure it's always the right).  It lasts anywhere from a couple of hours to a day or so.  I've had it for several years, just every once in a while.  I always thought it was related to cold weather but now I'm not sure.  I'm from Seattle and it seemed to happen after being outside in the cold and wind but maybe that's just a coincidence.

Now I live in Arizona.  I went to San Diego for a couple of days a few of weeks ago and it happened there, but didn't last as long as it usually does, just for an hour or so.  It was cooler there than it was here in Arizona but still in the high 70's.

Then it happened about a week ago here in Arizona.  Up until this one I was still thinking it was some sort of cold weather or moisture in the air or just a difference in temperature that was causing it.  This kind of blows that theory, although it's possible that the barometric pressure was high or some weird thing like that.

Then this afternoon the pain started again.  This time the temperature did drop down to the high 70's (from around 100).

I don't know if the weather thing makes any sense at all.  Any suggestions as to what might be causing it?  It's really awful.  It's the worst pain.  I'm waiting for my insurance to start so I can go see the dr about it.

thanks much!