Suggest Treatment For Constipation

I m having really severe pain in my right side lower back and its radiating to my right front side and stomach. it s been feeling kinda achy for several days. I woke up this morning with gas pain. I started feeling a little better this afternoon then an hour after I ate the pain has gotten worse. I ve tried going to the bathroom, because I feel like if I could go I d feel better but I m really constipated. Should I just take an over the counter gas relief or do you think it is something else