Headache on the left side. Starts pain.

It can be because of many reason from simple reasons like not sleeping on time or sleeping too much, stress, have long hours of fasting, dehydration to causes like sinusitis, migraine, high blood pressure, tumor etc. Do this 1. Take adequate night sleep 2. Eat at regular intervals. As starvation/gas can trigger headache 3. Avoid things that can trigger headache. Common triggers include alcohol, caffeine or poor sleep. Inculcate good sleep practices like having a regular bedtime schedule and avoiding naps, caffeine and TV before bedtime. 4. Don't take stress- Pursue an enjoyable activity or verbalising frustration to reduce stress and improve mental health. 5. Avoid foods that you know triggers your headache. 6. Hot packs and heating pads can relax tense muscles. Warm showers or baths may have a similar effect 7. Drink water. “Dehydration can be a big cause of headaches,” For this homeopathic treatment is very effective For more details you can consult me.