My pain management doctor started me out on 10mg Opana and I never taken it before so I started having palpitations in my heart.He changed my med to 15mg MS Contin(MorphineSulphate) and I have had no relief.In the past I had a collapsed lung when I was 18 and they had me on a morphine drip in a IV but my body would not respond.My doctor refuses to change me again from MS Contin.Has anyone else had this problem?