Hi!Go to a chiropractor or physical therapist. You may find it is another joint, or even you neck causing the issue. LOL
I already seen similar complains is cyclists.
The most common causes:
1. Median nerve compression(neuropathy) in the wrist - too much weight on handlebars, riding posture too low , etc
2. Cervical root neuropathy from cervical disc degeneration, foraminal exostosis or other similar problems.
This case is more serious than simple median nerve neuropathy , but more rare and seen in persons > 55-65 years.
You had better see a healthcare specialist.
PS. When You feel numbness and weakness in 4-th and 5-th fingers , the ulnar nerve compression may be a cause in your wrist from bad riding posture or too hard handlebars.