“Metatarsalgia” is the medical term for pain under the ball of the foot, and is a common complaint. There are many possible causes for metatarsalgia, and diagnosis requires careful assessment and sometimes further investigation.

Morton’s neuroma (interdigital neuralgia) occurs when the interdigital nerve between the 3rd and 4th toes (or sometimes between 2nd and 3rd) is trapped between the metatarsal bones and becomes inflamed. It is more common in women and inappropriate footwear has also been implicated as a causative factor. 
Symptoms are typically pain under the ball of the foot when weight-bearing in narrow shoes, like walking on a stone.  Occasionally there is pain and numbness shooting into the affected toes. The diagnosis is usually made by careful examination and diagnostic tests.
Many patients can be cured with the use of sensible footwear, insoles and in some cases a steroid injection (40-60% do gain benefit). An operation for excision of Morton’s neuroma is only advised after failure of conservative measures.

Other causes for metatarsalgia include inflammatory arthritis (e.g. Rheumatoid), Freidberg’s disease, Plantar plate rupture or mechanical overload (e.g. Pes cavus, bunion or hallux rigidus, previous surgery).