Breast cancer with bone mets

I am new to this site! After 6 years my breast cancer has spread to my neck and ribs. I have had a bone-scan, 3 CT scans(chest, upper abdomen and lower abdomen) and an MRI scan of the neck. Based on these  a tumour was found in C5 in my neck and I have lesions on my ribs. I had 3 weeks of radiotherapy on my neck and am now having monthly infusions of Zometa and take Aromasin daily. After 3 months the pain is less but I am worried now as I feel nothing has been done about my ribs and ddespite no other findings elsewhere at the time of diagnosis in May this year, I am now having some discomfort in one of my hips. Should I be doing anything else? I have just heard of PET CT scans. Is this a better alternative to MRI, which I feel I can never go through again, I was so distressed being enclosed in the "tunnel". My oncologist says we will do another tumour marker blood test to check on my response as one of them(presumably) breast cancer(?) was elevated 3 months ago. Is this an adequate indication?

Thank you!