My period is 4 days late and my nipples are hurtn can I b pregnant

If you have had sex, yes you could be, wait about another 4 or 5 days and do a pregnancy test if it has not started by then

It's certainly possible if you have been having sex. You could wait several more days and see if your period is just late, which can sometimes happen, or you could try a pregnancy test now, making sure to follow the directions carefully.

If you had browsed around this site a bit before posting ,you would have found dozens of similar questions. You might also have learned that ANY time you have penile insertion you run the risk of pregnancy. The symptoms you describe could indicate pregnancy, but it could indicate something else. The only way to tell is to take a test according to the instructions. Even then there could be false positives. So if you do get a positive reaction, you follow it up with a visit to your doctor.