Hi, I Am A 32 Year Old Male. I Have

Hi, i am a 32 year old male. I have been using a light pill steroid on and off for the past two years for gaining muscle. About a year ago while Going off a steroid I started developing a lump in my right breast underneath my nipple but to the right side of it. It is somedays bigger than other days and it is hard and sensitive to touch. Is this or could this be cancer or is it because of the steroids.
Thank you.
Regards,
Jeremy