Shouldice Hospital is receiving 10,000 emails a day from all over the world, and (I assume) hundreds of phone calls. Their "customers service" can be slow, understandably. Pain is considered chronic one year after the operation.
I found statistics of chronic pain for Shouldice Hospital - page 2, in the last paragraph after the Table 5 and before the heading "Key Features". It is 1%, according to R.Bendavid's "unpublished data". He is a former surgeon of this hospital, currently the president of American Hernia Society, more writing than operating lately:
http://cme.medscape.com/viewarticle/416375
_2 (you might have to register, but it's free and they won't spam you).
Another statistics is here, from the United Kingdom, with relatively small number of follow-ups - 146 patients. They report 12% incidence after 3 months (which isn't a chronic pain yet), then exclude 4 patients that were cured by oral analgetics after 6 months and one who didn't show up again, and arrive to 9% of chronic pain. After nerve blockade injections (plus one surgery to re-attach the mesh) the number went down to 2% (3 patients out of 146).
http://www.pubmedcentral.nih.gov/articlere
nder.fcgi?pmid=17853638
Nobody in medical world, unfortunately, is interested in pain statistics before 3 months, except for reasons of workers compensation (return-to-work time). 6 months seems to be an official recovery time, and with my mistrust in official statements I would think it's more like 12 weeks.