Very severe pain in the heels. Suggest.

My mother aged 47, has been going through heel pain for more than 18months now. It started with normal pain in the heels, which we assumed could be because of age and can be cured with comfortable shoes/slippers/silicon heel cushions. We went to a multiple doctors, and one of them suggested Kenakort injections. The injections were very painful and it only worked for 3months. Now the pain has started again and its difficult for her to even stand on her own feet. After few hours of continuous work/standing she starts to feel the pain in the heels and then it gets worse by the end of the day. We are not able to find a solution to atleast  minimize her pain. Lately she has been experiencing pain in the whole foot and near the ankles. The pain is generally on both the legs, but its more on the right foot. Kindly suggest.