I hate to tell you but I too was taking HCG back in November
and also found a hard lump afterwards. It turned out to be breast cancer
and I had to have serveral surgeries and am currently undergoing chemo and will follow up with radiation once my chemo is over. My cancer was hormone receptive, so the HCG made it grow, whether it was there beforehand I'll never know. I also have to have my ovaries removed due to the hormone receptive cancer.
I warn any woman taking HCG against doing so.