Your mobile phone is always being tracked by the cell phone company. It is a necessity in order for you to make and receive phone calls. Your mobile service provider can simply pinpoint your location by measuring the strength or weakness of the signal relative to three cell towers. With this, you can be found within a few hundred feet. If you would like to know whether your phone is being tracked by someone other than the phone company there are a few telltale signs.
Check to see if your phone is still warm in between phone calls. While it is normal for phones to heat up during a call, they will usually cool down within 30 minutes after one. If your phone is still warm even when it has not been used in hours then it could still be transmitting, which is an indicator that it could be bugged.
Check to see if your phone is interfering with the radio even when it is turned off. A cell phone bug will transmit your location at all times even when the phone is turned off. While it is normal for a phone to interfere with a radio when it is receiving or making a call, it is not normal if this happens when it is turned off.
Check for signs that your battery is draining faster the normally. If the phone is bugged, you will notice that it drains much quicker than it would normally. This is because it is constantly transmitting even when it is off.