I am a pedorthist and have been making custom foot orthotics for over twenty years and specialize with athletes.
Sorry for the long reply.
A diagnosed heel spur sounds worse than it is and usually isn’t the source of pain. It’s really just a way for the body to reinforce or anchor the plantar fascia at the calcaneus. What is does indicate is stress to the plantar fascia. Some people get the increase bone mass at the base of the Achilles tendon called a Haglund’s deformity. The Achilles tendon and plantar fascia are so close to each other that they are almost integral.
We have found that the main stress to the plantar fascia is lack normal pronation (land on outside portion of shoe then moving across the foot to the inner most tip of the shoe). Lack of dorsiflexion at the ankle (tight posterior leg muscles and psoas) and or lack of big toe dorsiflexion as the foot pushes off causes a tug of war. After a while an injury to the fascia, inflammation, angry nerves and muscle spasm sets in. During this phase running through it doesn’t work. Re-evaluating footwear, rest, stretching, ice, heat, not sleeping with toes pointed, ankle/foot ROM exercises usually help the most. Cortisone can really help but may be short lived if cause isn’t fixed. Multiple injections and even one for some people may break down tissue causing potential structural failure. If ice doesn’t help at all then maybe pass on the cortisone.
Big toe dorsiflexion is really important! Some people have a structurally stiff big toe and most of us have a functional stiff big toe. This means the toe moves upwards unweighted but the ground and foot compression causes the stiffness and doesn’t bend at toe off. It’s like a long stick. You can usually tell if this is happening if you have a big dent at the tip of the big toe when you take out the shoe’s insole, have a callus along the inside of your big toe, developing a bunion, and abduct or adduct when walking or running.
A few things you might try to help take the stress off the big toe is a running shoe with a good balance of cushion, neutral support and a very rockered forefoot. This will allow the foot to move from heel to toe unhindered. A gentle over the counter arch support may also help.
I really like to suggest Currex insoles as they come in three different arch heights and don’t restrict the arch, the new Asics Nimbus 25 is outstanding and Oofos recovery sandals for around the house. Thicker Hoka, carbon plated and other inflexible shoes can help some people but can hinder others as the forefoot is supposed to move three dimensionally. Unless you have a rigid big toe or arthritis try to get shoes that move with your feet.
Lastly the plantar fascia fans out from the heel to ball of your foot so an injury can happen in a number of places. Also if you have medial heel pain, foam roll your medial calf as it flexes your toes. If you have lateral foot pain, foam roll your lateral calf as is supports the outside of your foot (peroneal tendon).
If nothing seems to help consider seeing a chiropractor who is good with feet or get a nerve test for tarsal tunnel syndrome.
I’ve had it myself and it really sucks! Just try to make sure nothing is working against how your lower extremity is functioning when moving forward and be patient. One day it just goes away : )