Even after taking several treatments for abdominal pain and stool problem, there is no relief. Why?

Hello doctor,

I am a 74-year-old male. My problem is pain in the lower left quadrant of the abdomen and sometimes it radiates to the right also. It is persisting for more than 67 years.

All my problems are stated below:

I have mild to severe pain in the lower left quadrant of the abdomen sometimes in the right also. Stool does not appear normal and there is no feel of complete evacuation. When I leave the washroom again I feel urge to pass stool and gas. I pass gas frequently at short intervals.

First time I was hospitalized for this where I was treated with some medicines including Flagyl, Maxaform and some other that I do not remember. I felt some relief but the condition returned. I took treatment for IBS and E.coli, H.pylori, etc. I feel relief for some weeks but the condition returns. When I do not pass gas, I feel great pain in my knees and other joints and weakness in my legs. There is no problem in my upper part of the abdomen but the lower left part has this problem. I develop a lot of gas in the evenings and when I try to pass stool, only gas is released with some wetness in the anal opening.