I went on ClinicalTrials.gov and looked up a newer drug lu-177 which seems to help with bone met pain. One trial reported In those with bone pain, it was reduced partially or completely in 58%. There may be other drugs also?
Below is a link to the site and looks like some trials in CA. and NY. These are difficult to get into. Look for the trials that say "recruiting". Read through and see if they meet your needs and then you will need your Doctor to champion your case to them. They are trials so there are no guarantees... etc. Other search words may yield different list of trials.. etc. https://clinicaltrials.gov/ct2/results?cond=prostate+cancer&term=lutetium-177&cntry=us&state=&city=&dist=
You could also look into External radiation therapy which can relieve bone pain.
See more options below.https://www.cancer.org/cancer/prostate-cancer/treating/treating-pain.html