What Causes Pain And Pressure In Abdomen On Having Food?

If I cannot have a Bowel movement on my own and have to drink magnesium citrate to get relief but then as soon as I eat something again, the pressure, tenderness, pain, discomfort and the feel of a lot of ball like forms on my side come right back and can also feel larger clumped ball like forms together and hurt. What is causing this? It is getting to the point I don t even want to eat solid foods. Please Help!! I am so miserable!!