Yes, your channels are likely being changed by a neighbor. Fortunately, it's easy to fix. The following is from the Dish 522 Remote Control User Guide:
SETTING UP TO CONTROL THE RECEIVER
When you get the remote, it’s already set up to control the receiver on address 1. However, your receiver may be set to a different address. To set up the remote and receiver on the same address, use the following instructions.
1. Open the Important System Information screen. Consult your receiver user’s guide for instructions on how to open this screen without using the remote control. For most receiver models which use this remote, press the SYS INFO button on the receiver front panel.The Important System Information screen shows a Remote Address.
2. Press and hold the SAT mode button about three seconds, until all the mode buttons light up, and then let go of the SAT button. The SAT mode button will blink.
3. Use the number buttons to enter any number from 1 to 16. The SAT mode button goes out after you enter each digit, and then lights up again.Write down the number you entered:
4. Press the POUND (#) button.If you entered the address correctly, the SAT mode button will flash three times.
5. Press the RECORD button. If you are using an IR remote, you must point the remote control at the receiver while pressing the RECORD button.
6. Make sure the Remote Address on the Important System Information screen now is the same as the one you entered in step 3. If it isn’t, the remote can’t control the receiver.
7. To check the remote control address, press and hold the SAT mode button for three seconds. Then, let go of the SAT button, and press the POUND (#) button twice. The SAT mode button flashes the same number of times as the address you entered in step 3.
8. Press the SELECT button to close the Important System Information screen.
