Pressure on top of head accompanied by some feeling of light-headedness and reportedly crackling, is a brain parasite - likely neurocysticercosis, but could also be a round worm. Also golf ball sized headache is indicative parasite is still viable.

The only test is a blood test and the sample MUST BE REFRIGERATED IMMEDIATELY and CONTINUOUSLY. 30 days of albendazole + 10 days of Praziquantel and anti-inflam/histamine is typically required, but read National Institute of Health site before going to doctor.

Note MRIs for diagnosis useful in later stages.