Mother on palliative chemo since 3 years(weekly for 3 of 4 weeks, she use cortisone after each session for 3days).now, she is in 1-month break.now, she feels huge pains in her legs(most likely she become addictive to steroid).any idea to reduce pain?

If you are 73, she's 90+ or is she the 73-yr-old? The med schedule isn't clear. You say its hydrocortisone but how much? If she gets it 3 days in each wk for 3 wks, then a wk off she could be withdrawing, but only to the degree she does every 4th wk. The leg pain is ominous for blood clot, infection, or other complication of her disease which you also don't identify. She should SEE HER DOCTOR NOW