I'm 23,female,virgin.i always have severe pain in lower abdomen and hard stool for 2-3 days post masturbation by crossing thighs.i could even see 2-3 pimple like small bumps on either side of labia minora,used candid b cream but dint go away.serious?

Multiple issues but: Each person with constipation needs to be sure there is no other disease causing it. If constipation is just due to slow movement of the food and poop through the gut, then the things to try are vegetables, water, prune juice, prunes, fiber-with-water, polyethylene glycol, Senokot or other senna, milk of magnesia, other laxatives... A doctor can evaluate and maybe prescribe helpful medicines too.