is someone listening to my cell phone calls
To know if someone is listening to your cell phone calls, you can watch for some signs. Some are an overly warm battery and taking a long time to power down. To see other signs to watch for, look here: http://www.makeuseof.com/tag/6-signs-cell-phone-tapped/.
Someone might be listening to your cell phone calls if you are in a room with other people. You might also have someone listening to your cell phone calls if someone has gotten a warrant to intercept calls.