I have not had sex I have masturbated before I am having a burning feeling right in front of my period hole the doctor said there's nothing wrong but what do I do?

Have you had a urine test done?
Sounds like you may have a urine infection.
Take a urine sample to your doctors and get him/her to test it for infection,if this is the case you will be given anti-biotics,which will clear it up very quickly.

See your doctor again take a urine sample with you.