Pimple like, bump and itchy on my labia minora. what can cause it?

Likely a cyst : It is possible that you have a small sebaceous cyst. These usually are asymptomatic unless they become infected or become really large. Also bartholin's cyst can occur near the entrance of the vagina. Cysts usually occur from blocked ducts causing secretions to build up. Best thing to do is to see your doctor if it does not improve or resolve in 2 weeks.

See gynecologist: You should see a gynecologist as soon as possible. It could just be an infected hair follicle but it could also be an std. It is always best to get it diagnosed by gyn so you can get the best treatment.