Hello and welcome to HCM, Pain and stiffness of hip joint, back pain and inability to stand straight are suggestive of some local hip and back disease process. These symptoms are unlikely to be associated with breast cancer. Back pain and inability to stand are suggestive of inflammation of joint spaces, spinal canal stenosis, slip disc, bad posture to name a few common causes. Pain and stiffness in hip joint can also be due to similar pathology like inflammation, narrowing of joint spaces in the hip joint. A MRI of lower back along with hip joint is required to assess the joint space and condition of surrounding soft tissues. In case there is slip disc in lower back, rest and pain killers can help to reposition the disc back in place. If the slipped disc does not re-position itself spontaneously, surgical correction may be required. Hip pain and stiffness may be due to narrowing and inflammation of joint spaces. Anti-inflammatory drugs may be helpful to resolve the pain and stiffness. I suggest you to consult an orthopedician for clinical assessment and thus management. Thanks and take care Dr Shailja Puri