That's right. hadith is considered as the 2nd source after Quran. By the way I'm Muslim sunni. Anyway, back to the subject.
DID YOU KNOW that Quran took 23 years to be complete?
DID YOU KNOW that Quran is over 1300 years old and been saved?
DID YOU KNOW that Quran tell stories?
DID YOU KNOW that science and information such as mathematics, biology, chemistry, grammar and geography can be found in God's words in the Quran that you don't understand it?
Al-An'am, Versa 125
"So whoever God wants to guide - He expands his chest to [contain] Islam; and whoever He wants to misguide - He makes his chest tight and constricted as though he were climbing into the sky."
What this versa says if God wants to guide a human to the right path, the right way, the human will feel like he can breath with ease and comfort. If God wants to misguide the human, the human will feel hard to breath as if the human goes up the sky. By the way, this is my wording it. If you check more sources, they explain better than mine.
Now in science, it is known that the higher you go up the sky, the harder you can breath.