Is this doctor an OB/GYN? Did your doctor also do a pregnancy test? You said that you've done this before........stopped your bc pills and your period came at it's regular time. Was anything different this time? Are they the same brand and dosage? Were you on them for the same amount of time? Has there been a lot of stress in your life since you stopped taking them?
Birth control pills have changed so much over the years. Back in the 60's when my girlfriends and I took them, they were SO strong, they totally messed with your head and body. When we stopped taking them, it took some of us way more than 2 months before we got another period. I think my point was going to be that just maybe your body isn't ready for a period yet. Perhaps the sore nipples are a sign that it IS getting reading. And you know the more you worry about it, the more tense your body will become and that can delay the start of menses.
Did your doctor tell you to wait a couple of weeks and if you still hadn't started, to come back in? If sore nipples are uncommon for you, what did he/she say about that?
Try some really hot baths, that can sometimes bring on a period. But if you are REALLY worried, if the doctor you saw was a GP, go see an OB/GYN. If the doctor you saw WAS an OB/GYN, get a second opinion.
I can give you some possibilities, but only a doctor is going to be able to give you an answer.
Peace
Greenlydia