There are several different possibilities here. The most simple would be that you are having sun burn or sun damage to the ears. This is actually pretty common because the skin on the tops of the ears is thin and sensitive to the sun; however, we often forget to cover the ears with sunscreen or to protect them from the sun!
The other most likely possibility would be that you have eczema
on the ears. This is also quite common. Eczema is a condition in which the skin becomes dried out, resulting in redness, flaking, and itching, and it can occur on any part of the body including the ears. Eczema can usually be treated easily with avoiding harsh drying soaps and personal care products, by regularly applying a thick moisturizing ointment, and by using an over the counter steroid cream such as 1% hydrocortisone.
If these methods do not work, then you should go see your primary care doctor
. Sometimes eczema can require more potent steroid creams, which your doctor can prescribe for you. Additionally your doctor will be able to make sure there is nothing more serious going on - for example, a precancerous spot on the skin of your ears.