Mortons neuroma typically occurs between the 3rd & 4th metatarsal as the nerve sheath that runs between it is 'pinched'. What you're describing is more likely associated with the head of the second met' which sits slightly lower than the other four. As such it is commonly affected by extended bouts of walking/exercise. In extreme cases you can develop Freiburgs syndrome, or 'march fracture' - so called due to a large number of soldiers experiencing such problems following drill practice. Either way, rest is all that is needed with perhaps some padding, for a week or so. If the problem persists, seek a GP referral for X-ray to confirm whether there is indeed a small fracture. REST & ELEVATE.