I was taking 2 500 mg of vicodin every 3 - 4 hours at the time
Watch out there with that. Vicodin does nothing for pain for the most part, has lots of Tylenol that kills your kidneys and you are supposed to get at most 6 500mg a day, not as many as the 16 a day you claim to be taking.
I found when I was trying to pass stuff that lots of water and a few Advil helped more than Vicodin.
PS: I buried a friend last year that was taking about 15 of your pills a day and dies, so be careful. With all the Tylenol in Vicodin, you could be swelling up your kidneys with just that. Maybe look into altering your drug therapy.