Can anyone help diagnose or suggest relief for base knuckle/ MP joint pain in my right ring finger?

I've had various pains at the base knuckle joint in my right ring finger for over 4 weeks now. I am very active, golf, basketball, weightlifting, and bowling. I do not recall any direct trauma and woke up one evening with what felt like a throbbing heart beat in my right hand. The pain is localized, sharp and throbbing and comes and goes. A few days in, I would practically forget about it unless I "triggered" the pain through basic activity, ie picking up my laptop, opening a bottled drink, shaking someone's hand. Any grabbing or fist clinching action triggers the shooting pain. The pain is also present when the right ring finger is pushed outward toward the pinkie. X-rays were negative at the Ortho and he put me in a splint, but the pain is significantly worse when removing the splint after one week of wearing it. He asked about a history of gout or arthritis, but I never had any swelling, burning, bruising, etc. I believe it has to be MP joint inflammation from overuse, tendinitis, or maybe an ulnar nerve issue. Has anyone experienced something similar? I'm 32 and in good shape, so I don't believe it can be associated with weight, diet, etc. Please share your input. Thank you.