Hey jman, +1 for Miralax here. My fissure was killing me BAD summer of last year and the pain wasn't tolerable until I started taking Miralax and eating veggie soup all the time. I also used nitroglycerin ointment and it helped, but by itself didn't make my days passable in any sane manner until I added Miralax. I'm not all the way back yet (I've had a few setbacks along the way) but I no longer live completely terrified of every bowel movement. Miralax takes a few days to "kick in" so if you're not doing it now, start ASAP. There's still no guarantee that your fissure will heal even with Miralax, but it's almost guaranteed to be more tolerable, so at least it'll buy you time until you decide to try LIS or BOTOX or whatever your next move is.
Trust me, I know it sucks bad right now, but most of us here have been to hell and back with fissure related problems, and Miralax has been a Godsend for many of us. This isn't worth ending or ruining your life over, please give stool softeners a try -- if Miralax doesn't work you can always try it together with some of the other ones like docusate sodium too -- and then decide if you want to try conservative treatment longer or get LIS.
Also, if you're having bad spasms, Valium has helped some of us here with that, so it may be worth asking your doctor about. It shouldn't be used long term but can most definitely help in the short term.
BTW do you go to Mizzou? I grew up in Columbia, right off Providence Rd in the University Heights apartments.