My son had an ear ache last night. somtimes ear drops can be painfull. Now he was already on medication for a cold( first dose given today). I gave him a pain reliever, but knew that would take time. So, I contacted my local hospital. The nurse on call suggested I place salt ( any amount) in a sock and heat it in the microwave. once making sure it wasn't too hot. I then put the sock under my sons ear while he was lying down. I placed about half a cup for one minute on high. There is no exact amount that would be right. enough to cover the ear while lying down. also a thicker sock is better than a thin one. Place an elastic band at the end or tie. Some will leak out, but totally worth it. After that my son only woke once more. I know the pain reliever helped. But the warm salt really helped sooth him.
An old trick for relieving earaches is warm salt in a cloth heated in the microwave as you have or will read in the comments here. PLEASE be very careful when microwaving socks & clothe they can and will catch fire. 30 seconds at a time is plenty if not warm enough heat 5-10 sec longer.