Regarding bubble bath etc please read the labels very very carefully.
I worked in a laboratory studying the effects of surfactants on the environment.
Lauryl ether sulphate - LES; Sodium lauryl sulphate - SLS and any other products with similar names were the primary 'ingredient' in persil automatic during the 70s. It's even in dermatological shampoos available on prescription for scaly scalps ffs.
Shampoos and bubble baths that contain traditional soaps are likely to be glycerol esters, so you'll see names like glycerol stearate on the list of ingredients instead of all the sls, les crap that shouldn't go near the human body.
Incidentally, I worked with fabric conditioners, too. They are more powerful than washing soda in removing the oil from your skin, and they are a cationic detergent +vely charged ( washing powders/liquids are generally anionic -vely charged).
I used to have such a pain, too. It felt like a sort of cramp. It was diagnosed as vaginisimus, but I don't think it really was. I think given my personal circumstances at the time it was down to really intense desire/randyness and a need to 'grip' something iyswim.
It can still happen if I read erotic fiction that's well written, but at least I know it's not painful sex and tell myself to calm down! 
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