I have had my phone since March. In early June it started doing this thing where it vibrates at random times throughout the day and night. I can't determine any association between the vibrations and anything else going on with the phone. The vibrations are brief bursts that seem to occur in pairs spaced about a minute apart. Sometimes hours go by with no vibrations, and sometimes they seem to occur very frequently. The phone usually becomes very slow to respond to my commands during the intervals between vibration pairs, and the apps won't behave properly. I tried contacting Samsung customer service but they did not respond. Has anyone else had this problem and found a way to fix it?