Hi Doctor, I have pretty bad pain in my left elbow, and cannot completely lock my elbow straight - when I try – a lot of pain - is this bursitis - or something else?

Elbow pain can be pretty debilitating, especially when it limits your motion. Bursitis of the elbow usually presents as a warm, red, fluid collection at the back of the elbow (almost like a golf ball on the back of your elbow). It usually doesn't limit your motion. There are a couple of things that come to mind with this history. One possibility is that you are starting to develop arthritis in your elbow. The best way to diagnose arthritis is with an x-ray. Another, more likely possibility is that you may be developing a tendonitis in your elbow, either of the triceps tendon, or "tennis elbow" or "golfer's elbow". These conditions are caused by overuse and cause pain in the back of the elbow or on the sides of the elbow. The best treatment for these is rest, gentle stretching exercises and anti-inflammatories. I hope this helps.