Cubital tunnel syndrome is the second most common nerve entrapment problem after carpal tunnel syndrome While carpal tunnel affects your wrist, cubital tunnel affects your elbow.
As you lean on your elbow, the same way ever day, the body tissue surrounding the ulnar nerve that passes through your elbow to your forearm begins to press in the nerve. This is what causes the tingling and pain.
If the pain goes away not long after you’ve stopped, it’s possible there hasn’t been much damage, although you should get it checked. In the meantime, try to break yourself of that habit as the pressure on the ulnar nerve can only get worse if you continue to do so.