I recently noticed that my mid 2013 13" macbook air's trackpad is very difficult to click. I took it to the genius bar thinking that the battery might be swelling but they said the battery is fine. I decided to open up my air and check out the trackpad. I adjusted the clicker screw by the trackpad and it helped a bit but it still feels much harder to press than normal. Has anyone else had this problem and how did you fix it?