What do you mean by "someone" and "tracking?" Many, many apps send information on your location, so they are in essence tracking you. If you download an app from the Play Store, it will disclose what it has access to. Unfortunately, many people don't read it, and install apps that turn on their GPS and run down their battery.
In addition, if anyone has your gmail password, they can usually track your movements through the Google dashboard.
So, if you are really concerned about it and see something that makes you suspect that you are being tracked, the best things to do are (1) a factory reset of your phone, which will get rid of any tracking software/malware that has been installed, and (2) change your Google password and make sure that you don't share it with anyone. I would also enable 2-factor authentication for Google to make it harder for any unauthorized person to login to your account.