The answer to your question will depend on whether the bumps are new or painful and what the bumps look like. Unfortunately, it’s not possible to tell exactly what the bumps could be without a health care provider seeing them.
One important question is whether or not you have been sexually active with another person and whether or not you are using condoms every time you have sex. If you are having sex, it’s extra important to get a check up with a doctor, since sometimes bumps can be a sign of common sexually transmitted infections (STIs). Most STIs are easy to treat with medicine—but the first step is to make an appointment with your health care provider.
If you have not had sexual contact with another person or you have had these bumps since before you were first sexually active and they don’t hurt or itch, then there is probably nothing to worry about. However, it’s still important to make an appointment with your health care provider. Health care providers see this kind of thing all the time so there is no need to feel embarrassed and it will probably give you some peace of mind.