Once you have had a lung fungus, can it spread to your brains. Also, it will cause you to start having allegy?

Fungal infections. Fungal pneumonias are rare, but in those who have them (usually with some sort of immune compromise), it can spread anywhere, including the brain. That being said, allergic bronchopulmonary aspergillosis (abpa) is a syndrome where a fungus can lead to chronic asthma like symptoms and allergies, but is not an invasive infection and would not go to your brain. Talk to your physican.