Whether it’s a broken arm or acid reflux, pneumonia or shin splints—whatever your physical ailment—pay attention to your symptoms and sensations. Jot them down in your writing notebook, using language as specific and vivid as you can muster. This sort of detail often comes in handy when a character is suffering, and may work into a plot element.
The same is true of any strong emotions you experience, from euphoria to rage. Don’t just label it and move on. Be as specific as you can be on what the physical sensations and/or signs are—e.g., pounding heart, the heat of a blush, shakey hands, etc. Jot these in your notebook as well. They are great aids when you want to show a character’s emotions rather than summarize them with a label.