Is it safe to have colonoscopy with bowel narrowing, difficulty passing gaz like pushing through a straw, very small bm after pushing long time,no no urge feeling ,going on since a month x ray show partial blocage but scan no blocage?

All procedures have complication risks, influenced by findings and/or pathology and the physician’s experience. The presence of a narrowing may increase the risk for bleeding or perforation, but the overall yield of the procedure as far as diagnostic and sometimes therapeutic outweighs by far the risk. Your physician remains your best reference going forward, trust is critical.