Nope. But an insurance company can raise rates over what was quoted, for an entire small company by 35% because I have a benign stable condition that involves one blood test and $200 a year in medication. The following year they raised it another 25% and I was coincidentally laid off the day before the new rates were to take effect.
Has any first world government ever insisted at gun point that a citizen stay with government health care?
Sure. Many socialist countries have laws that prevent anyone from obtaining healthcare outside the government system. Canada is one. How does any government enforce it's laws other than at gunpoint?