I am at ten weeks now, and at worst my dilation is a messy nuisance by this time. My first couple of weeks though were fire on wheels. I had a minor set back though in the form of a yeast infection that turned every suture line into an open trail of pain when I inserted to dilator. When that was under control though, things were still uncomfortable and more than a little depressing, but I did learn some things that helped and have made life come to a point where I can deal with the discomfort.
Be sure you have enough lubricant on the dilator itself, but do not over do it. A film of lubricant all over it from tip to top mark, but so the stuff is not hanging off in gobs.
Take time as you are inserting the dilator, and slowly "tease" it into the opening, if necessary, rotate it a bit to advance it in to depth. The massaging of rotating it can help things. If you hit a sore spot, pull it back out and wait until the pain stops, and you will usually be able to go past the spot with comfort. The entire insertion exercise counts on your time, not just the time you are at full depth. Pumping the dilator just a bit keeps the tissue inside from pinching on itself. Ramming the dilator in like its a nail you are pounding into a board will hurt badly.
Body position helps as well, keep head low and put a thick folded towel under your hips to straighten out the vaginal cavity, keep the towel just up from your butt crack to avoid a problem there. Keep your legs with your knees up, and apart at shoulder width like you want to wrap your legs around a partners body when the time comes for penetrative sex.
As for the coughing and sneezing, I actually sneezed once, and I had taken my hand off the dilator to cover the sneeze, I shot the darn thing out about six inches from my crotch. If you feel a sneeze or cough coming on, pull the dilator out half way, and it will become bearable.
If you are still having real pain though, check with your surgeon, or go to a gynecologist if your surgeon is miles away and have them see if there is a real reason in the form of a yeast or other infection.
I did not believe any of this when a friend first told me either, but give it a try, and you can fib about discovering this all on your own!!