Several years ago - actually, around 8 years ago (I'm 68 now) - I was getting a lot of discomfort in my left elbow. It was a year where I had increased my mileage and difficulty level. I also was starting to experience some knee discomfort. I ended up getting a bike fit at my LBS. One of the things he did was to swap out the handlebars - replacing with a narrower one - idea being there was less pressure on the elbow from long rides and road chatter. I was fortunate in that that did the trick with no need for any medical attention and I haven't had a problem since (knee discomfort resolved, too, thankfully).