I'm 23 and recently had my periods but after skipping a month. My periods were normal and after two days when my periods end I had a date. I'm a virgin. My boyfriend tried to have sex but after just pushing against my skin when he was not in, I cried out of pain so he quit and we didn't hv sex. The problem started after that. My vagina started to itch externally with the areas joining the leg and back in the butt crack. I have washed it, applied petroleum jelly and it relieves me for a while but it returns back. I don't have any bumps, odor or unusual discharge but this itching doesn't go away. Please help.

That is enough contact to get some type of infection or STD, no one online can guess, you need to see your doctor and get tested.

Both men and women can get either STDs (sexually transmitted diseases) or infections.
Google STD and see the list of diseases.
Infections are either bacterial or yeast. Both are present on our skin and everywhere.
Bacteria get under the skin through a tear in tender tissue or a cut. Yeast develop when your pH is out of balance. Bacteria require antibiotics and yeast can be treated with drugstore products such as Monistat.
Men are more likely to not know they have an STD so you need to be tested.
But it's quite likely that you just have yeast.