I have pain at the base of my thumbs all the time - it's osteoarthritis. It's just something I live with and take glucosamine for, which helps. But it does affect my ability to do things like pushups and plank work and pikes! as well as I'd like. I generally have to stop and rest my wrists for a bit, then go again, so it doesn't stop me from doing the moves, it's just one of life's little inconveniences. x( I'm gonna try the perfect pushup handles too.