Deut 28:58 – If thou wilt not observe to do all the words of this law that are written in this book, that thou mayest fear this glorious and fearful Name, THE LORD THY GOD ; 28:59 – Then the LORD will make thy plagues wonderful , and the plagues of thy seed , even great plagues of thy seed , even great plagues , and of long continuance . 28:60 – Moreover he will bring upon thee all the diseases of Egypt , which thou was afraid of; and they shall cleave unto thee. 28:61 – Also every sickness , and every plague , which is not written in the book of this law (e.g AIDS ) then will the LORD bring upon thee , until thou be destroyed . 28:62 –  And  shall be left few in number , whereas ye were as the stars of heaven for multitude ; because thou wouldest not obey the voice of the LORD thy God.

Disobedience is what brings sickness in your life. Live an obedient life unto God and His word and stay healthy.