Now you get to be a 'detective' and try all the suggestions.
Not touching your face is a big one as is washing your hands right away after being in the store.
See if it is the yarns or not. I can't get near wool.
Please share the result with the owners/management of the store. It may be something simple like dusting the floor multiple times a day that will help.?.
Years ago they used to use formaldehyde to preserve thread. I was pregnant with my now 44 year old son at the time I learned this. My hubby was horrified and made sure I didn't put the thread in my mouth when threading a needle [I didn't and still don't.]
ali