My wife Eileen has been getting them since around 2007. Before then she regularly used an Ultra Light Arms .30-06 with full-power 165-180 grain handloads, and a couple of light 12-gauge shotguns.
Her first recoil headaches were with one of those shotguns, but soon afterward she couldn't shoot a Ultra Light Arms .270 with 130-grain loads. But she's had to steady step down since then.
Today her "big" rifle, used for elk, is a .308 Winchester with 130-grain Barnes TTSXs loaded down to around 2850 fps, and year or two after starting to use it she also added a muzzle brake. Her deer/pronghorn rifle has been a Tikka .22-250 for the past several years, using the Hornady 70-grain GMX bullet at around 3300 fps. Her shotguns are usually either a 28-gauge SxS for upland or a Browning Gold 20-gauge autoloader for waterfowl, a gas gun that also mitigates recoil.
It doesn't generally have anything to do with stock shape (much less powder fumes) but how hard and fast the butt-end hits the shoulder. Like Eileen, many people find recoil headaches get worse with time, mostly because people's bodies become less flexible with time.
