3. Sex relieves pain. Orgasm is one serious narcotic! Oxytocin, a naturally occurring chemical in the body surges during and after climax while working in conjunction with a few other endorphins to make sure you feel no pain. In his book, How to Treat Arthritis, rheumatologist Carter V. Multz asserts that sex can reduce pain, swelling, and inflammation associated with arthritis, headaches and menstrual cramps.