The guy in the room next to me isn't well mannered, so I have trouble sleeping because I can't relax with him there.
この場合、次のような言い方ができます。
ーThe guy in the room next to me isn't well mannered, so I have trouble sleeping because I can't relax with him there.
「隣の部屋の人のマナーが悪くて、彼がいるせいでくつろげず、眠れない」
ーHe's kind of loud when he talks on the phone, he plays his music too loud, and then he gets mad at me when I make any noise at all.
「彼は大きな声で電話したり、音楽を大音量で聴いたりするのに、私がちょっとでも音を立てると怒ってくる」
ご参考まで!