I have been on Tricor for about two years, but due to creeping up...

I have been on Tricor for about two years, but due to creeping up in my cholesterol numbers, my doctor has put me on Zocor, too. All has been fine for about six mos., but recently I have been having soreness in my upper arms/shoulders, which I attributed to having lifted something heavy and driving for a very long distance. However, that was over a week ago, and it has not gone away. In addition, my feet hurt all the time. It is the muscles in my feet and I have difficulty walking, after sitting for awhile. All I have read points to the Zocor, but I am wondering if the combination is the real problem.