Hello, it could just be coincidential having trapped up the distance resently and having pain at the 5th metatarsal on loading. There are quite some possibilities which you have to consider. I'll name some; trainers changed resently or used for to long. stress fracture of 5th metatarsal which gives a slight swelling (diagnose by X-rays). Nerve impinchment called Morton's neuroma. Major issue could well be foot biomechanics; if the arches of your feet have dropped this will cause extra stress on e.g. the 5th metatarsal, could cause a nerve impinchment. to get some impression if drop of arches is part of the problem, you sit down barefoot take a good look at your feet, stand up and if the foot has changed a lot in form, widened especially the forefoot this could well be the cause of your problem. But e.g. in case of a stress fracture, the result of poor biomechanics, you need to offload. To be honoust I suspect that seeing either a Podiatrist, your Gp or a physiotherapist would be the best idea in case of persisting pain. E.g. stress fractures seem to give pain at night, unfortunately nerve pain could do as well.