I been on depo-provera since i had my son last year i got pregnant with him on the depo-provera but now i'm still on it in late last night my nipples started hurting in still are now could i be pregnant?

Apparently so: The reported effectiveness of Depo-Provera, a progesterone-type drug, injectable is reported at 99%, so your experience of getting pregnant on Depo is certainly rare. And as they say .... "if it happened once, it can happen again!" Check a pregnancy test or two, a week or two apart, and then review with your doctor if there are alternate methods of birth control for you ... ? also use a condom?

Yes, small chance.: Statistically, the chance of getting pregnant while on Depo is 0.3%, or 3 in a 1000 women per year while on Depo will get pregnant. Since you got pregnant before on Depo, it sounds like a standard dose may not be sufficient to suppress ovulation in your body. I suggest a pregnancy test. If that is negative, please check your breasts for discharge and lumps, as that needs evaluation.