So I went into the doctor because I'm having excruciating pain in my arms and chest due to weight lifting and he prescribed me 16 5mg Vicodin. I took 2 right away and after a half hour or so I didn't feel any effect and it wasn't helping the pain so I took a third and 15 minutes later it's still not doing a thing. Is it possible the Vicodin won't even do anything for me? Could it be because of my weight (I weigh 340 lbs)? With the prescription it says not to take more than 8 in a day, but is it possible that I may have to take 4 vicodin for every dose every 4 hours?