Re: small painful bump
Hi, we appear to have the lump in the same location, from what I have read, these lumps often appear on the sole of the foot, and mine is not quite on the sole, but just where it meets the sole. I just discovered mine in almost the same way as you did, didn't notice it until I flexed my foot.
Hoping you have found a solution to your issue. From what I have found, flip flops might not be the best shoe to wear, as they do not give you enough arch support and that may be contributing to your issue. I live in flip flops, so this has been the most difficult step for me, but trying to always wear shoes with some arch support.
Also, I went to a Podiatrist and was prescribed Verapamil Gel for the problem. It has apparently had some success in the treatment of these types of masses. First step, you really need to have the mass evaluated by a Doctor. There are many things it could be, and you don't want to take any chances with your feet! That is why I went running to a Podiatrist upon discovery of the lump.
I don't have a true diagnosis as of yet, but there was a suggestion of it being Plantar Fibromatosis (however that is most often seen on the bottom sole of the foot), which is what I think is complicating my diagnosis, as it is not truly on the bottom of my foot. Of course you have to notice that is most OFTEN seen on the bottom, therefore it could be located elsewhere and still be Plantar Fibromatosis. You might want to look into that possibility.
Most importantly, with any foot mass, HAVE IT EVALUATED BY A DOCTOR. I can't stress this enough from the research that I have done.
Would love to hear how things are going and if your issue is resolving.