Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.
There are several causes of headaches. Headaches can be divided into primary and secondary. Primary headache disorders are headaches without a direct cause. These are diagnosed after secondary causes have been excluded. Secondary headache disorders are due to an underlying problem, there are many many causes but some include medication side effects, systemic illness, nervous system infection, tumors, bleeds in the brain or clots in the veins of the brain, and others. Elevated blood pressure could potentially cause headaches but would be much less common in your age group.
Primary headache disorders are much more common than secondary ones. There are several primary headache disorders, over 50 different types. For example migraines, which usually a pulsating throbbing one-sided pain with nausea and discomfort in bright lights that lasts several hours. Tension headaches can cause band-like or pressure like pains, and when muscle tension is present, sensitivity if the scalp such as in your case can occur. There are several other types of primary headache disorders.
Without further information about your headache, it is difficult to provide you with adequate information, and to determine whether or not your headache is a primary disorder due to stress or otherwise, or whether or not it could be more serious. However, it is important for you to understand that if you have not experienced headaches in the past and you are now having new head pains, seeing a neurologist is a good idea, just to make sure there is nothing serious causing this pain. Imaging of the brain and sometimes neck may be indicated depending on your exact symptoms, your physical examination, and other factors.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.