Hi i have had x rays and mri on elbow and they were all clear and showed up nothing , but the nerve is flipping in and out the groove and pain?

Try meds, bracing &: exercises. Antiinflammatory meds like ibuprofen may decrease inflammation of the nerve, bracing to avoid keeping the elbow bent, especially at night, and doing flexion and extension exercises of the hand at the wrist may stetch the tissue and give some relief. See https://orthoinfo.aaos.org/en/diseases--conditions/ulnar-nerve-entrapment-at-the-elbow-cubital-tunnel-syndrome/