Is There Any Substitute For Naproxen To Treat Waist Pain?

I am taking naproxen tablet. Even I took pentasole before taking naproxen my stomach hurts. What. Can be substitute for naproxen. That will not make my stomach hurts. I fall down n I have tissue and muscle torn according to dr. Thanks god no fractures but it hurst a lot.my right side below the waist .thanks .what could be your advise. I also take Tylenol with codeine. But I stop. For sometimes it makes me constipated though I took weetavites. Cereals. Thanks.
Flora