Thanks for posting your query at DoctorSpring.com
You seem to be having the beginning of a urinary tract infection.
This is very common in females , particularly around the time when they begin to have sexual activity.
It is partly due to friction from recent sex, and partly due to urinary infection, as female urethra is quite short.
You should drink lots of water, atleast 5 litres per day, particularly a lot of cranberry juice.
Also, get a urine routine microscopy and urine culture test done to know the severity of infection and need for antibiotics.
Avoid rough sex meanwhile, use lots of lubricant such as KY jelly.
Avoid fingering or oral sex till you are cured completely.
Use condoms all the time to prevent flare up of infection.
Keep your private parts very clean.
Avoid using artificial or medicated soaps, gels, cleansers, washes, just use lots of water to clean down there.
All the best
Please feel free to discuss further.