If you have been ordained as a pastor do you need to be ordained as a deacon?

No you don't. The Higher office covers for the lower office.

Exodus 20:8-11

It depends on the denomination. I am Southern Baptist and even there it depends on individual churches. I believe most SBC churches would say a pastor serving as a deacon does not need to be "re-ordained" but a deacon who wanted to become a pastor would have to undergo another ordination. You will have to speak to your church/association/state/convention/denominational leaders (whichever is appropriate) to determine the policy.

Edit:

There is no verse to cover this scenario. One can see that ordination was practiced, but there is never anything implied by Ordination other than that it was for Christian ministry. There was never a hierarchy given to this situation or of one type covering another (it is debatable whether they were different types, but this probably the case). This is why I suggested you look into what your denominations policy is. Most Baptist Churches will say that the church you are attending should make the call (but not all would say this).