Hi
Thanks for writing to the forum!
A hard moveable lump could be a lipoma, neurofibroma or a cyst. However it would be advisable to get a mammography done to rule out breast cancer. Along with self examination of breast also look for axillary lymph nodes. Repeated friction as by bra band can cause thickening of skin, an ulcer, a rash but not a moveable hard lump.
It is difficult to comment beyond this at this stage without examining the lump. Please discuss this with your doctor and see what he thinks about it. Please let me know if there is any thing else and do keep me posted. Take care!
Have the lump surgically removed and a biopsy of it. It is a good idea if just to be on the safe side and put your mind at ease. I have had too many friends and relatives told that they had cysts, when indeed it was breast cancer.