I can feel 4 lumps on my body, 3 on my stomach, and one on my back near my right kidney. They feel like they are on the outer part of the stomach and are not bigger than 1/4-1/2 inch diameter. One is near my sternum, one directly below it about two inches, one to the right about 2 more inches down, and one over my right kidney. They are only painful if pushed on but seem fairly hard. I am a 21 year old male, and worry about cancer. Any thoughts?