I am 60 years old. I had prostate cancer radiation two yearsago. My g was 7.25 and psa was 7; now my psa is 5.8.My bones get very sore at some places, on/off. Could it bebone cancer?

Unlikely. Bone cancer is rare in patients with psas under 20. As a mentor of mine once said, though "the good thing about cancer is that it gets worse." what he meant was that if you have had bony pain for a while and if it has not been getting worse, then it is unlikely to be cancer.
Intermediate risk. Commonly get androgen suppression, anti-hormones...If you are on that, your current psa is quite good, but not if you are still on hormones. It is highly unlikely that you have bone metastasis with psa at that level. My goal is for psa to be <1.0 at 2 year from completion. Tell your doctor, evaluate benefit of bone scan at this time...I doubt it will help.
Psa. Given your psa level it would be unlikely to have metastatic pca.