OP, you are not at all unreasonable to ask the government to let us know how long the mask-wearing will go on.
Equally you are allowed to hate it but comply, as a lot of people are doing.
To the person who posted about having to wear them in cars in Hong Kong - I hope the government is making sure masks are available in all sizes and fits. Like a few PP, my mask rides up my face and pokes me in the eyes. There is absolutely no way I could drive safely while wearing one. I cannot see the road!
In fact I would like to see move disposable masks available in different sizes if this is a long term thing, as one size most definitely does not fit all (I'm sure they are designed for men, like most things). It's easier to get a good fit with a cloth one but I can't manage to get enough air in through 2 layers of cotton and a filter when it's 35 degrees outside. I'll probably return to the cloth one in the winter.
Wearing masks when it's very hot can absolutely have a bad effect on your health. I was at the GP on Monday (34 degrees in the shade), wearing a mask as is obligatory, and my blood pressure was 192/116. It's normally highish (hereditary) but well controlled with medication. I have no idea how many times it has spiked like that; I've certainly felt unwell many times when wearing a mask but what choice do I have? Do people think that because my blood pressure only effects me it is tough luck? I was allowed to leave with instructions to monitor it, but the doctor was hesitating about admitting me. Once I removed the mask, returned home, and cooled off, my BP returned to normal levels. I will continue to wear the mask because I don't want to die of Covid, but I don't particularly want to die of a heart attack or stoke either, so I'll be avoiding non air-conditioned places until after the summer.