Brief Answer:
Most probably Planter Fascitis and Rx as advised

Detailed Answer:
Hi.
Thanks for your query, albeit short and specific.
To recapitulate: Female/45 - painful bottom of foot and heel to walk on - wants to know what it is and what can be done to feel better ...

This is most probably planter fascitis.
You may do the following for getting it better:

Take broad based bucket or a bowl in which you can rest your both feet comfortably.
Pour in a water till it fills up to 8 inches. Remove the feet and start adding common salt to the water. Go on adding till you can see the salt not being able to dissolve. This makes it supersaturated solution.
Once this saturated solution is made, you have to make it warm on a stove to an extent that the back of your hand can tolerate, pour it into the bucket, test the temperature again, rest your feet in to the bucket. Keep part of the solution on the stove so that you can add warm solution to the bucket with feet. Continue for 15 minutes minimum twice daily. Do not throw away this solution as it will look dirty after some days; use the same.
An anti-inflammatory medicine like Ibuprofen if it suits you.

You may take an additional oral steroids in the form of Deflazacort under the prescription of your Doctor, in tapering dosage only if other treatment fails and is not contraindicated in your case.
Diuretics if needed.
Low salt.
Weight reduction.
Elevate the feet above heart level in lying down position.
Always take multivitamins as they act like anti-oxidants.

I hope this helps you as it helps many of my patients.
Please feel free to ask for more if you need to and you may please rate this answer once you are satisfied with the answer.

Wishing you an early recovery.

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