Suggest Treatment For Pain In Elbow

I am a 23 year old male. Months ago, I fell on my left elbow while playing outdoor hockey (no elbow pads). There is no pain in the elbow. When I bend the arm, it's like there is a "hole" over the olecranon. What is this and is it a problem that should be checked out? Again, there is no pain and the no noticeable movement/stiffness problems.