I think this is a mis-reading of Matthew 7:7, as well as a message that is not taught in the bible. A better interpretation would be that Matthew 7:7, rather than talking about diseases and worldly troubles, talks about entrance into the kingdom of heaven, where all we need to do is knock. Here's a good source for that that draws on other sources: https://www.blueletterbible.org/Comm/guzik_david/StudyGuide2017-Mat/Mat-7.cfm

In addition, nowhere in the bible is a promise made that everyone who asks will be healed, nor that family life will always be good for Christians. This sounds to me like the prosperity gospel teachings, which aren't necessarily biblical and are often more damaging than beneficial. Please see this article about the prosperity gospel:
https://www.thegospelcoalition.org/article/what-you-should-know-about-the-prosperity-gospel/