hey I have had my mac book pro since early 2010 and have been beginning to notice that when I use it and it is plugged in to the charger cord the left side of the bottom of the computer gets REALLY REALLY hot! It cools off if I unplug the unit, but sometimes I want to work plugged in. Plus I am just not getting the battery life I used to get. On average I have about 4 hours of battery.... Used to get 7+. Any thoughts?