Earlier quoted context omitted.
The ACA reduced the rate of price rises, so it can't possibly be the cause of the price rises.
You and sol_remmy are talking about two different things. You are talking about overall expenditures in the health care system. He is talking about insurance prices charged to individual purchasers, in particular ones that are relatively young and healthy.
sol_remmy seems to be making the case that lots of sick people didn't have coverage before ACA (Which would be a massive plus point for it if true) and that the number of new sick people buying insurance outweighed the number of new young, healthy people entering the pool, driving costs up.
There seems to be a lot of conflicting info on this, but at least Brookings made the case that the expected effect of ACA did actually happen, lots more people started paying for insurance and the average cost paid by individuals therefore went down (even while the average coverage they could recieve went up).
So we seem to be talking about the same thing, just with radically different facts about the same situation.