Herceptin pain, am I crazy?

I was diagnosed back in October 2015 and began Chemotherapy in November. I completed 4 rounds of 4 different chemo meds that took 8hrs to infuse , then another 4 rounds of 4 different meds that I had to be admitted into the hospital for 4 days at a time because they required 24hr infusions. Along with all this treatment I've been taking herceptin infusions every three weeks and will continue them until November. Now for the side effects....in the beginning it was mostly horrible mouth sores that made it difficult to eat, fatigue, muscle aches, back aches and peeling of my hands and feet. Of course I lost all my hair but that's a given and at one point during the second round I could barely walk because the bottoms of my feet hurt so bad. But we realized it was worse when the treatment was too close together. (Every 2 weeks instead of every 3 ) now I'm only on herceptin and I've had this horrible ache in my hip flexors on both sides as well as severe lower back pain. My Oncology nurse doesn't think herceptin is to blame and my Oncologist seems stumped too because the pain is in both hip flexors not just one. Finding something to lessen the pain has been difficult. I've tried several different pain meds and chiropractic therapy but the pain is still there. Is herceptin to blame? Am I doomed until this is all over? Will the pain go away when the herceptin is finished?