My DS13 is very open and honest and last night told me that he has a lump behind his right nipple. He let me feel it and it is a pea-sized hard lump and he says its tender to touch. I'm assuming this is just his hormones kicking in as he as started the eat-everything in sight and growing at an alarming rate etc. Have any other MN had similar experiences or should I take him to GP to get checked?