If there is no damage to the ligaments, what you are experiencing sounds like inflammation of the hyaline cartilage in your elbow. This happens as a result of releasing pitches with a supinated grip (olecranon process bangs into its fossa) and can lead to long-term damage in the elbow, such as lengthening of the ulna bone, loss of flexion about the elbow, and eventually UCL tears.
Can you post a high-quality video of you throwing from the side and rear views? This would help a lot.
Do you throw sliders? Have you thought about pronating through release?