Long lasting soreness in big toe?

My big toes feel sore, as if they're a little bit bruised on the tip, whenever I put any pressure on them. This has been going on for over two months I think. I've wondered whether I might have an ingrown toenail, but my toes don't look sore of red, and I would be surprised if I'd had that for so long without it getting better or worse. The only change in these last months is that I've been wearing flip flops almost constantly. I'm wondering if continual wearing of flip flops might put too much pressure on my big toe when I walk, and if I stop wearing them the soreness might get better. If anyone has any insight on this, and if the flip flops are really a plausible cause, I'd really appreciate it!