Hello I Am 74 Year Old Woman Until Recently I

Hello I am 74 year old woman until recently I have been riding horses. Now I have been told I have a bulging disc in lower back disc sand 4. My leg is altered to touch and my knee is swollen and numb it is the inner part of the leg I will need a knee replacement,what I am wondering is would this condition cause extreme pain in the buttocks when getting out of bed it feels like intense cramping and it goes away after awhile after activity I have been taking prednisone for polymyalgia and i have taken myself down to 4 and intend to go down 1 each morning as they put on weight and the extra wieght dosen't help so is the buttock pain cramping and inflamation or is coming from a degenerative back and bulging disc??? thank you Anne