Stop gathering evidence by repeated cycling
If one normal command produced a hum without movement, note what happened and stop retrying. More attempts do not establish which component failed. Keep people and vehicles clear if the door is uneven, partly open or visibly damaged.
Describe the sequence you already saw
Was the door fully closed beforehand? Did the sound begin after an outage, impact or earlier difficulty? Tell the service provider whether any indicator changed and which control was used. Share observations as a sequence rather than naming a part you think must be broken.
Ask for a system assessment
The motor, drive and moving door need to be considered together. Request an explanation of the finding before choosing repair or replacement. An assessment that identifies the cause gives you a better basis for a quote than buying a remote or stronger opener on speculation.
Your questions
Should I pull the release to investigate?
Do not disconnect or manipulate a door that may be damaged or unsupported. Let the technician decide how it can be assessed safely.
Does humming mean the motor has failed?
Not necessarily. Similar sounds can accompany different problems; the symptom alone does not justify ordering a motor.