How Can Lower Backache While Suffering From Pneumonia Be Treated?

I am home sick. Just got out of hospital with pneumonia. Chest X-ray las Monday showed it. After being on antibiotics for almost two weeks my doctor ordered another chest X-ray yesterday, exactly one week later. He said it was worse looking than the first, but when I went into the emergency room last Monday nite with fever and chills and a splitting headache, I had no complaints about my chest. In fact I had worked out that evening. I was shocked when they ordered the first X-ray and diagnosed me with pneumonia. Anyway as the week went on in the hospital my headache lessened and I began to feel more chest pressure. The last few days were the worst. Achy, fatigued, no appetite, short of breath. Definitely not myself. Hence the second X-ray. When he called he was ready to send me for a cat scan, but for the first time I feel better. The only thing is I have developed a lower back pain. Yesterday it was on my left lower back, today it is at the base of my spine. Very sore and difficult to move around. He said to call him tomorrow if it’s still there. He said it’s rare that it’s related. Rare but could be. What do you think. I am a teacher and have missed quite a few days as I couldn’t even imagine walking to my classroom from my car! Thank you for any input you can offer me!