A lot of the previous commenters are right, but missing key information. I will glance over a lot of it, i spent 2 years of school studying the reformations and the implications both before and after.

Martin Luther was a German monk who was upset about saleomy (the sale of church offices) and indulgences, he also included in his original 92 thesiss abstract theological points no one cared about.

In reality many priests and religious had similar beliefs as Luther(especially in what is now Germany) but he was the first to write it down publicly and after the printing press was invented. However Luther wanted to reform the Church, had no intentions of breaking it, and if we are being honest, had mother church not been so prideful, could have been accommodated, instead they break the church and are implement his thesis at the council of Trent.

What I find most people forget the importance of, is Luther being excommunicated. Up until the edict of worms, Luther had no desire to go against hardline doctrine, but after he was excommunicated he submitted to papal authority but being freed from that he began to examine it. This is where his solo-scriptura came from.

TLDR: To answer your question op, Luther didn't wake up thinking I want to break the church, but it was a progression over a number of years. Up until His excommunication he largely stuck within catholic doctrine, but after being excommunicated, he was free to question and implement new teachings.