I too get blocked sometimes and man it hurts , hurts like hell no matter how much pressure you put on the seat nothing seems to move out . I asked my surgeon why is it so that I get blocked only after dinner and after working out. His response was you are not drinking enough water to keep your gut going. I stopped eating bananas before workout as they are hard to pass through and I feel like if during workout I loose more water they get stuck inside causing blockage. Also my surgeon advised me to have pysillium husk with milk and that works for me everytime now.
Also lettuce is mostly water so it does cause too much gas or liquid stool. High protein meals can be a bit gassy so try eating some carbs everytime, bananas, breads, pasta will help here alot. You can also eat peanut butter to supplement healthy fats and iron tablets with a multivit tablet daily.