I have been trying to figure out what is causing my elbows to get this dull pain in them after I workout. I have run through all of the obvious suspects in this order: weight lifting, swimming, doing pull ups and climbing.  My elbows hurts after a little while of doing all of these activities.  However, not so much during climbing.  This morning I was doing some stretches and they hurt my elbow.  Thus I think it is safe to assume that simply extending my arm fully for an extended period of time aggravates it.  Sometimes I swear I'm made of glass.  I'm definitely going to go see a doctor about this....I wonder if it might just be a pinched nerve or something.