Are These Different Color Spots Under My Nipple Normal? (photo)

The color of the nipple is varigated and pale or darker spots can be common. Also size is most often uneven right to left so things seem quite normal. You are young to be concerned about breast cancer, and cancer on the nipple (rare) appears as a rough rash. Pigmented spots even while young deserve an exam by your family physician.

None of what you  point out is alarming in any way. There are variations in color in all patients, and is most noticeable at boundaries where the colors change, such as here at the edge of the darker pigmented areola next to lighter breast skin.

No one has perfectly symmetric breasts, and yours are somewhat more asymmetric than other's. If they bother you enough, a consult with a plastic surgeon can help sort out the options to improve the symmetry.

Neither the color variation or the asymmetry is suggestive of breast cancer or any other disease process.  If the breast pain persists a discussion with your personal physician is appropriate.

Thanks and best wishes.