Thanks for writing your query.
Single sided headaches
can be due to migraine and cluster headaches.
I would suggest you that you should go for a MRI head and neck to rule out other possibilities.
You can take pain killer like Ibuprofen
one tablet twice daily after meals along with an antacid like Omeprazole
40 mg for severe pain
Following precautions may be helpful :-
1. Avoid missing a meal.
2. Avoid emotional/physical stress.
3. Drink lots of pure water daily.
4. Have adequate sleep.
5. Avoid cigarette/alcohol, if any.
Clinical examination and investigations will help to plan your medical treatment.
I hope this is helpful to you.