What Causes Right-sided Headache With Swollen Lymph Nodes In Armpit?
Just above the neck junction
Detailed Answer:
I read your question carefully and I am sorry about the health problems you have been having.
Regarding your question, by crossover I assume you mean where the fibers originating from one side of the brain crossover to innervate the other side, correct?
The area of the crossover is in the part called medulla oblongata, which is situated at the lowest point, above the junction of the head and neck. So if your fear is that the right-sided headache is related to a direct spread of those left-sided infections you've had to the brain that shouldn't be the case.
As for the cause of the headache I am afraid some more detail is necessary to narrow the list of potential causes, as headache causes can be many. Some info on the: characteristics of the pain (throbbing, pressure like, sharp), persistence (episodic - if yes how long or constant), duration and manner of onset other accompanying symptoms (nausea, vomiting, vision issues, sensitivity to noise and light, fever, lacrimation, eye redness, ear pain, nasal congestion and discharge, weakness or numbness in the limbs, high blood pressure etc).
I remain at your disposal for other questions.