It´s possible that you aren’t earning as much money as you should be in your job. This could be down to the company hiring you at a low wage when you were new and naive to the working world or alternatively to them not increasing your wage fairly for your years with the company. Take a look at employment data on the internet to see if you are earning what you should be in your area, if not, start looking elsewhere.
If the doctor has advised you that you need to stop working due to health problems, the best course of action is to do exactly as he says. Your health is the most important thing and the state has ways to help people who are deemed unable to work.
It´s quite common practice for a company to hire an employee as a junior and promise him big things within a set amount of years as long as the junior employee commits and does his duties well. In many cases due to the naivety of usually young employees in this position, they will conduct well but the bosses will add more and more work and responsibilities without increasing pay or title. This can go on indefinitely, if you are a victim of this then it´s recommended to speak with your boss about a raise and a promotion and if he still doesn’t listen, if possible, go above his head.
Some employees are in the habit of overworking their employees beyond their agreed hours and worse, beyond the legal limit of house. If an employee puts 40 of their workers to work an extra two hours each per day for a month that totals around about 320 hours per month of free labour. If your boss is pulling you back each and every day to give you extra work you need to talk with HR. If nothing comes of it and it continues, you can quit and you have the ability to file a lawsuit against the company.
In this day and age it is nowhere near as common to encounter this, however it still happens. If you have witnessed or have been the subject of inappropriate behavior which includes bullying, sexual harassment, racism or anything along those lines then you have to right to take it to the top and have the employees conducting this behavior punished. It´s very unlikely, but if nothing is done about it by the company then maybe it’s time to move on. Nobody wants to be part of a company that condones this behavior.
Quitting a workplace is a permanent move, so make sure you have thought it over and that you have a plan B ready.