The paint was shaken at the store. I thought that would be enough. I didnt stir it with a stick. It only turned to a paste in some areas. If the paint wasnt stirred enough, wouldnt it do it to the entire ceiling ?

Explain. How does a thick paste dry? I am not able to visulize anything more than a dry white ceiling. So this is half a question

Just a guess....It wasn't stirred enough?