Ignition is usually the easiest of the three to check because on most engines, all you have to do is pull off a plug wire and check for spark when the engine is cranked. On coil-over-plug DIS systems, there are no plug wires so you have to remove a coil and use a plug wire or adapter to check for a spark.
Stress can affect every part of your body. muscle aches, head aches, how your hair grows, the texture of your skin, it can affect your menstrual cycle.
Stress is the body's natural response to threatening situations, and it affects everyone. Stress can be good, like buying a new home, or bad, like mounting debt. Either way, your body and mind react to such situations with a heightened state of readiness, which is called the fight or flight response. This reaction causes your brain to make hormones including adrenaline and cortisol.