I have a tender lump under skin on breast(male) between nipple and underarm. what could this be? concerned about cancer.

See below: At your age breast cancer is highly unlikely. It is more likely to be an infection. However it still warrants examination by a doctor for a proper evaluation.

Breast lump in males: It is very unlikely that you have cancer. There are many other conditions that may mimic your condition such as abcess, lipoma ( fatty cyst ). Get your doctor to diagnose what you have so you can stop worrying.

Male breast lump: A male at any age can have a lump in his breast, and a tender one may just reflect the number of times your concern made you pinch or compress it. The common cause is a sebaceous cyst, or a lipoma, both of which are benign, but see a health care professional to be certain. A malignancy is extremely uncommon.

Bump: It's difficult to tell in this type of arrangement what your concern is . I would tend to believe that based on your age and other factors probably a lipoma which is a small collection if fat tissue and not dangerous but men can have breast cancer too. Get it checked by your doctor. :)