Hello and welcome to the DROID forums 
it sounds like you have a run away app but I don't see one.. you might try downloading an app like gsam. It has a feature called app sucker..it might help to identify your issue..
My suggestion at this point is to try removing the battery for a few mins. Then reinstall it and try it out.
Also, are you using the factory supplied wall charger?? IRS important that you do on phones like the maxx... idk about the s3... but its a good habit to have
it sounds like you have a run away app but I don't see one.. you might try downloading an app like gsam. It has a feature called app sucker..it might help to identify your issue.. My suggestion at this point is to try removing the battery for a few mins. Then reinstall it and try it out.
Also, are you using the factory supplied wall charger?? IRS important that you do on phones like the maxx... idk about the s3... but its a good habit to have