When I push the button to open my garage door, the

They are not light weight but there is no reason if the motor can raise it, then you cannot raise it by hand.

Sounds like you have a chain drive garage door opener and you hear a humming sound when you push the wall console. The motor is running but the chain does not move. You need to replace the gear & sprocket assembly.

Garage door motors have sealed bearings, but you can add grease to the threaded rod, or chain, and squirt wd-40 on moving parts.

Is the trolley jammed against the bolt just in front of the motor? If so, loosen the chain until the tension is off the trolley and then run the motor until the door is closed. Now locate the up limit on the side of the motor unit and turn this control 2 full turns in the opposite direction of the arrow printed on the cover. Tighten the chain.

You may have a bad drive gear or a bad start capacitor. Remove the cover from the motor unit and it will be obvious if the drive gear is bad.

Is the door stuck in the open position? If so the trolley is probably jammed against the bolt just in front of the motor unit. Loosen the chain enough to free the trolley and then run the opener until the door is closed. While the door is closed locate the 'up limit' on the side of the motor unit and turn this control 2 complete turns in the opposite direction of the arrow printed on the cover. Tighten the chain.

Try this link
http://www.garagedooropeners.us/helpgifs/chamberlain_troubleshooting.html

pushed it too long. push 1 second and recode keypad. you wiped out codes by hitting for 6 seconds or more

You gear is stripped out on the inside. If your feeling handle you can change it your self open up the case and you will se what I mean right away. Take the gear off and go down to sears they have a part that will work for your opener. make sure to have the opener and chain in the down postion.
liftmaster/sears/chamerlain are all made by the same company so many of there parts work together. But now all of them

you will have to find were the chain is binding look around the drive sprocket and check the chain to see if it is tight at the bottom or top this will tell you were to start looking for the problem.