33 week preg. Modrate dry cough (no mucus) and stuffy nose. Cough give me stomoc pain, dr. Priscribe me codeine/promethazine syrup 5ml 3times/day is ok?

Most likely safe... It is always hard to gauge how safe a medication is during pregnancy. Both of the drugs you mentioned are class c which is defined as drugs that have not been shown to be harmful to fetuses, but data is limiting; use if benefits outweigh potential risks. I guess i would ask how bad was your stomach pain from the cough. If it wasn't too bad, i wouldn't take anything (the safest alternative).