In the past year I realize that I increased masturbating everyday sometimes 2 times a day probably because of watching too much porn. I noticed that after I masturbate I get low abdomen pains, weak feeling around waist, constipation and tailbone pain for a few days afterward. Could this be related to too much masturbation and why does this happen?

Yes, it can.
It is a direct result of abnormal serotonin levels, along with heightened inflammatory response for excessive cortisol, epinephrine, norepinephrine, histamine, and prostaglandin E2.