Thanks for posting your query at DoctorSpring.com
You could be having vaginal dryness due to lack of lubrication.
This can lead to infections, breakage of the surface of the vagina etc.
You need to consult a gynecologist and get the following tests done -
1. Internal exam
2. Vaginal swab
3. Pap smear
4. Pelvic ultrasound scan.
Right now you should use probiotics ( take lots of curd and yoghurt in your diet ).
Do not use ANY ARTIFICIAL PRODUCTS to clean private parts - no soaps, gels, cleansers, douches, special feminine washes etc.
These can lead to worsening of the infection and dryness.
You should just clean with lukewarm water and pat dry gently with a towel.
Try and use a lubricant such as KY jelly with a finger to moisten the private parts.
Do not wear synthetic nylon underpants.
Wear cotton panties and change often.
Please cut back on your weight too as sometimes when you are overweight, the thighs rub against the private parts, resulting in more irritation.
If you can upload photographs of the area, I can tell you if this looks like something specific.
All the best
Please feel free to discuss further.