When driving My Solara over 65-70 mph steering wheel shakes badly VERY BAD Why?

What is your question?

Also when I am going around a curve it actually seems like the front tires on both sides are shaking to the point I have to slow down when braking the steering wheel shakes badly as well it happened after I had 4 wheel alignment as well as wheel balance and tire rotation done it got worse what could be wrong PLEASE HELP?????