Could there be something wrong with your brain even if you have no symptoms?

Of course, but...: No healthy person should worry about stuff like that. Life is not perfect, and we humans have things wrong with us... every human has something, and that's just the way it is. Statements like "could there be something wrong even if you have no symptoms" are true for every part of one's body. Thus, doctor's do preventive care to screen for the MORE LIKELY disorders. For rare disorders, no worries.

Brain vs Mind: If you have no symptoms like headache, pain, loss of memory etc. and are functioning normally, your brain is probably working at a normal pace. Your mind, which is the emotional/intellectual part of your nervous system, can be effected by stress, your physical condition and anxiety. Learn to relax, continue to be engaged in your vocation and get medical evaluation regularly to ensure timid health.