Is one who cannot sleep except on his stomach sinful, and is this disliked or forbidden?

A Muslim sleeping on his stomach is disliked due to the hadith of Ya'ish bin Tikhfah Al-Ghifari, may Allah be pleased with him, who said: My father said: While I was lying on my stomach in the mosque, a man started nudging me with his foot and said, "Indeed, this is a posture that Allah dislikes." I looked up and it was the Messenger of Allah, peace and blessings be upon him. Also, because the Prophet, peace and blessings be upon him, saw a man lying on his stomach and said, "This is the posture of the people of Hellfire."

Therefore, it is preferable to be careful not to sleep on one's stomach and to train oneself to sleep on the right side.