What Could Cause Persistent Left-sided Head Pain, Frequent Forgetfulness, Restlessness, Fever, And Loss Of Appetite?

I am 20 years old and have completed my education recently and have started working, Since 3 years i am experiencing a minor headache only on half side of head. I visited hospital and showed to doctor thinking its migrant but they said everything is fine and i am not suffering from migrant. But now as time passed by the pain has increased and most of the time i experience pain on left side of the head and along with that i forget things too easily.
Symptoms of diseases are:
1. Fever most of the time
2. Forgetting things too easily
3. Feeling restless without doing anything
4. Pain on left side of the head most of the time
5. loss in appetite