Pain in thumb joint
I'm wondering what the source of pain in my thumb is, and what I can do about it. My left thumb (non-dominate) has sharp pain at the joint where it meets the hand when I squeeze something or press it towards the palm. Some pain when pulling away from palm, but not as much. No pain when not in use. When i poke around and squeeze the joint I find painful spots, especially on the palm side. There is no pain on other parts of the thumb, hand, or wrist.
This seemingly happened overnight, although there was no trauma or injury that I know of. I just suddenly noticed it.
I am a 29 year old male, use my hands frequently including gardening and playing guitar (which really hurts), and have no history of pain in this hand. There is no visible swelling or differences from the other thumb. Pain has been persistent for about a month and has neither diminished nor increased.
Thanks for your time!