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.
When the stress is gone, the body reduces its output of cortisol and DHEA to resting levels and everything is fine. This is what happens with short episodes of stress. However, when the stress is prolonged, the body prefers to make increasingly greater amounts of cortisol and less DHEA.