Why couldn't sickness be chastening or trial of faith? Job was sick as a trial of his faith. Deut 28 shows that sickness can indeed be chastening. Do you ever get sick?
Deuteronomy 28:58-61 (NASB)
58 "If you are not careful to observe all the words of this law which are written in this book, to fear this honored and awesome name, the LORD your God, 59 then
the LORD will bring extraordinary plagues on you and your descendants, even severe and lasting plagues, and miserable and chronic sicknesses. 60 "He will bring back on you all the diseases of Egypt of which you were afraid, and they will cling to you. 61 "Also
every sickness and every plague which, not written in the book of this law,
the LORD will bring on you until you are destroyed.
The important thing to consider when you are applying Scripture, is to consider who is the intended audience. Moses was writing to Old Covenant Jews who were under the Law. It was not written to New Covenant Christians who are born again, new creatures in Christ.
You see, the Bible was written for us, but not always to us.
You are misquoting the Scripture and applying things that Moses taught to people he never intended to apply it to.
Job did not see his sickness and misfortune as a trial of his faith. There is no mention in all the book that Job actually exercised faith in his situation. Faith is always based on the Word of God. Faith comes by hearing the Word of God. There is no mention anywhere that God gave Job His Word until right at the end when He was about to restore Job to health and to restore all the other things.
God cannot put upon anyone the diseases that existed in Egypt, because Jesus was whipped, fulfilling Isaiah's prophecy that by His stripes we are healed. Jesus quoted Isaiah in context with His supernatural healing ministry. Peter quotes it in the past tense to show that now that the Atonement has been made, healing is an accomplished fact for all New Covenant Christians. All we have to do is to believe it.
I think that you need to do some serious Bible study to find out the difference between the Old and New Covenants.
If you are still living according to what Moses taught in Deuteronomy, then maybe you are still in the Old Covenant where you are expected to keep the whole Law without one infraction. If this is so, you may not be born again. You may still be at the stage of being a believer in the same way that unconverted Jews were believers during the time that Jesus was on earth before His death and resurrection. You might be like Apollos who only had the baptism of John, and you might need a genuine born again, New Covenant Christian to explain the Way more perfectly to you.