Fibromyalgia can get worse for a number of reasons. Some are related to your environment, while others are related to your own body. The most common cause is when you’re under stress, and the body releases hormones that cause pain. It’s also possible that your body is overreacting to pain signals or that you’re not producing enough natural pain relief chemicals in your brain. In terms of what’s going on around you, it’s important to be aware of the things that can cause fibromyalgia to flare up. For example, if you have certain types of injuries or illnesses like rheumatoid arthritis or lupus, this can trigger symptoms of fibromyalgia.