Let's see.

原因 and 缘故 both mean the direct reason when some things happen,缘故 emphasizes the reason,but 原因 emphasizes the relationship between the reason and the thing.Similar meaning.

亲身 and 亲自both mean doing something yourself,亲身 emphasizes the experiences that you get by yourself,亲自 emphasizes the status(or identity).So when a person of high status or influencer do something himself,use 亲自 more natural.

I'm a student from China,so my English is not very well.Hope my words do help.