How bad is it to keep taking laxatives? will this permanently affect the stomach movement?

It won't : If you have chronic, severe, constipation the chronic use of laxatives or stool softeners is not really harmful. You should discuss the details with your doctor. If you have bleeding, abdominal pain, weight loss or diarrhea, further evaluation may be necessary. See your doctor.

It can: Chronic use of stimulus laxatives can cause a "burn-out" of the nerves in the colon requiring increasing doses of the laxative leading to increasing problems with constipation. You should work at more natural means of having a bm, such as fiber, probiotics, fluids, exercise.