The most basic available are shoe inserts Migraine Care Review which are slipped inside your shoes and provide the support to your heel and arch area which could be lacking from your current choice of footwear. In their basic form, they can be purchased from your local drug store fairly cheaply.
I'd always recommend speaking to your doctor before purchasing these cheap options though as you may not be getting the treatment you need. The doctor will be able to tell you right away if simple shoe inserts are enough to give you the support you need. It is possible to have shoe inserts specifically made to fit your feet which will provide a much higher level of support than some off the shelf offering.
Plantar Fasciitis night splints could also be used which take the shape of almost a boot which covers the foot, ankle and lower leg area. These are intended to stretch your plantar fascia ligament overnight while your sleep which could hopefully reduce pain in the morning. Used in conjunction with shoe inserts you may find that this is a successful approach to treating this horrible condition.