If Allah has perfected our religion and Islam is the only faith acceptable to Allah, why does He allow Muslims to suffer so much?

Dr Shabir Aly gives us a quick summary of the possible reasons.

Allah sends trials to those He loves to make them better.

Because He loves us and better to suffer in this world (to atone for our sins) than the next.Perhaps because of our sin. Although we should not dwell on this but consider it as a possibility.To encourage us to seek forgiveness from Allah and closeness to Him.