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.
1 Nearly everyone experiences stress at some time. Stress produces changes in many body systems; examples include increased heart rate and blood pressure and altered immune function.  Some amount of stress is healthy, but excessive stress, left untreated, can lead to anxiety and illness.