Runners are at risk for Morton’s Neuroma largely because of the repeated stress that they put on the balls of their feet (and because they often don’t wear the proper shoes while running).
Although it can be a real bummer, it is highly recommended that you not continue intensive running while you are experiencing symptoms that could indicate that you have Morton’s Neuroma (or another foot condition). Instead, experts recommend that you switch to a different cardio workout that does not place as much pressure or repetitive stress on the foot.
Some add cycling and spinning to their routines because these don’t cause same amount of repetitive stress to the bottom of the foot. However, if you decide to take up these (or some other form of cardio) instead of running, you should make sure you have proper shoes, pay attention to the amount of resistance that you are adding to your workouts, and if you feel pain in the aggravated area of your foot–decrease or stop the exercise entirely.
Source: 5 MISTAKES THAT PREVENT MORTON’S NEUROMA PAIN RELIEF