Why didn't medieval people in England wear cotton?

Answer 1

The dominant fabrics of the middle ages were wool and linen. Both were produced in medieval England. Linen was used mostly for garments worn next to the skin, and wool was used for outer layers because of its better insulation and water resistance.

Cotton was known during the middle ages in Europe. It was produced in parts of Spain and Italy, in Sicily, and in North Africa and the Levant. The use of cotton had reached northern Europe no later than the end of the 13th century. It was not widely used in the north, however, because it had to be imported while linen and wool were abundantly available locally. There was also resistance to cotton by the guilds involved in the production and sale of wool, as they did not welcome the competition, which also helped limit the widespread availability of cotton.

So, there would have been some cotton available in medieval England in the late middle ages, but it would not have been common, and would have been imported because there was no local production.