Where does the constitution grant you unlimited free choice?
The current form of the constitution allows conscription in wartime. It is legal for your government to pass a bill forcing you to serve in the army against your will. You seem to think you have this magical thing called unlimited and total freedom as a constitutional right. That isn't the case at all.
Back in reality, the constitution does not make it illegal for the government to force you to buy something, force you to pay taxes, force you to abide by laws, or force you to serve in the military. It also doesn't make it illegal for you to have to pay specific taxes on things like alcohol or tobacco. All sorts of other bonuses and penalties are applied to taxes. Paying a penalty for refusing to get coverage is not any different than paying a penalty/tax or receiving a bonus for any of the other things calculated in income tax.