I have a dime size lump on the inside of my bicep about 3 inches below my armpit. When I squeeze it I get thick yellow / white puss out. Not runny....it s thick. It s only sore after I squeeze it and irritate it. Color of the bump is light red to pink.
Hi. Thanks for your query. The causes of the dime sized lump on the inside of the biceps muscle can be an infected sebaceous cyst as thick yellow / white pus came out on squeezing. Once you get the pus or contents out, the surface inside get in touch with each other to get soreness, and irritation. Color of the lump as light red and pink is obviously due to infection and inflammation. I would advise you to get a course of an antibiotic and anti-inflammatory like Ibuprofen for 5 days, have clean Chat Doctor.  Consult a Surgeon if the symptoms or the signs increase or if there is a recurrence in future so that a permanent cure can be done by a formal surgery.