Where does Tetsuos headache come from?
Not from the dope or something like that alone, that’s for sure. The army is interested in progress. To increase Tetsuo’s powers artificially, they use drugs and treat him with rays. But that’s a quite rude way to wake the Power within him. The drugs and the other experiments are quite dangerous. Tetsuo was lucky having only a headache; other test subjects of the project (not all of course) became mentally handicapped or died an unpleasant death. Oops. The next question offers more info on narcotics.