Hi there!
In addition to localized foot issues such as fasciitis, ligament/ tendon injuries, infections, inflammations, spur formation, heel fat pad syndrome, arch issues etc; vascular/ lymphatic issues, drug side effects and systemic issues related to the kidneys/ heart/ liver may need to be considered. I would suggest a primary evaluation by a primary care physician/ internist and depending on the cause diagnosed/ suspected, it can be managed accordingly or specialist car may be sought.
Hope this is helpful.
Take care!