The answer to 'garbage disposal constantly running' is that the disposal is likely jammed or stuck. This can happen if the disposal has become clogged with food debris or an object has gotten stuck inside. Symptoms include the disposal running continuously without actually grinding anything.
The solution is to try to clear the jam or obstruction. First, turn off the power to the disposal at the circuit breaker or wall switch. Then use tongs or pliers to carefully remove any objects stuck inside. You can also try using an Allen wrench or disposal tool to manually turn the blades and dislodge the jam. If the disposal is still not working, you may need to replace the entire unit.