Metatarsalgia is a meaningless term. It like saying someone has a sore knee. It does not tell you anything. A sore knee could be due to a lot of different things, so saying someone has a sore knee does not help convey anything.
‘Metatars-‘ refers to the metatarsal, the forefoot and ball of foot. ‘-algia’ means pain. So the term metatarsalgia means nothing more than pain in the forefoot and like a sore knee, the term is pretty meaningless and should not be used. There are literally 100’s of things that could cause pain in the forefoot and get labelled inappropriately as being ‘metatarsalgia’.
The different problems that could cause pain in the forefoot all have different causes and different treatments, so it is impossible for there to be one cause of metatarsalgia, let alone there being a treatment for metatarsalgia.
Pain in the forefoot could be a callus, a plantar plate tear, a Morton’s neuroma, Freiberg’s disease, a stress fracture, an osteoarthritis in the joint and many more. It should be clear from this short list is that they are all totally different, have different causes, different symptoms, different treatments and different outcomes.