It's common for emotional distress to be expressed through physical symptoms. Oxytocin and dopamine levels dip whenever you experience yearing for a person, and this could cause some physical discomfort such as the headaches you mention, or a spike in your heart rate and blood pressure.

As these are matters involving brain chemistry, there is no easy way to "fix" it. But now that you're aware, what you can do is to manage your feelings by grounding yourself and making sure that you are practicing a healthy lifestyle.

Take comfort in the possibility that every passing minute away from someone takes you closer to the time when you'll be reunited with them. That way, you can change your feelings of yearning into something more positive.