I am a 49 year old woman. I weigh 48 kg and am 5ft tall. Up until July I have been very physically active. Cycling, power walking, hill-walking etc. I have spent years doing kick boxing, horse riding and a variety of other sports. I eat well. About two weeks ago my right lung feels a bit heavy and hurts slightly. I have a slight cough and know that both the cough and the mucuous I am coughing up is coming from this lung. I am experiencing some unusual back pain which I never had before. It is not there all the time. The first time it hit was a couple of weeks ago. I just woke up with it (mid to upper back). Felt like I had fallen on my back. Felt fatigued, heavy limbed (especially my upper arms), had aches and pains all over as if I had flu. Stayed in bed for the day. Next day my shoulders and neck ached as if I had pulled muscles. Cleared after a couple of days but last Saturday a burning form of pain began to radiate from my lower back, down into my buttocks and thighs. Felt extreme exhaustion and aches and pains all over. It was gone the next day. These attacks of pain are accompanied by a feeling of having a temperature and am convinced I will be down with a flu the next day. My lung condition remains constant. I had a bad cold virus at the end of July. I haven't had a cold or flu in over a decade. I just feel unhealthy in my self at this stage and my body very weak. Do you think all these conditions are related?