Does anyone know how to relieve constipation other than laxitive methods?

I have been having really uncomfortable stomach pains on left lower abdominal. I went to the doc and he did a stomach xray and said I had backed up stool (sorry to be gross), and so he told me to take magnesium citrate and dolcolax and all those... So I did and only alittle bit came out but im STILLL having bloating and discomfort. Can anyone help me with this issue? Thank you.