I'm sensitive even to different sounds, light and various smells, and it's painful.
Even things like sound, light, and smell have become a source of mental anguish to me.
この場合、次のように言えますよ。
ーI'm sensitive even to different sounds, light and various smells, and it's painful.
「私はいろいろな音や光や匂いでさえ敏感で、苦痛だ」
painful で「つらい・苦痛な」
ーEven things like sound, light, and smell have become a source of mental anguish to me.
「音や光や匂いなどでさえ、私には苦痛になる」
to become a source of mental anguish で「精神的苦痛になる」
ご参考まで!