i have only had sex with one person for the last 4 years and just noticed this last night. no burning or itching and no pain really either. can someone please help me 
Most of the time ulcers are caused by sexually transmitted infections (STIs) but many other issues can trigger an ulcer - fungal infections, viral infections, bacterial infections and sometimes, common conditions like tonsillitis, upper respiratory infections, or a virus that causes diarrhea can cause genital ulcers, especially in adolescent girls.
There are several effective treatment options for these sores.
I would get that checked out by your doctor
oh, yes, and definitely get it checked by a dr or at the sexual health clinic.
have you found out what it is? or if its gotten worse? im getting test results back for mine today