I am a non US citizen that worked in California from Aug 2005 till April 2010
I paid taxes each year but am now living back in Europe but may go back to work in the states in a few years if my career dictates
I am trying to file my tax return for 2009-2010
When I resigned my job I had to wait 30 days then was able to withdraw my pension that had accumulated over the almost 5 yes of work. I withdrew all the pension & 20% was withheld as federal tax
I've got the 1099-R form and am trying to fill in my 1040 now
Will I have to pay more tax? I'm confused as to whether the IRS double dips or if I've paid my 'dues'

Any advised appreciated

Your 2010 tax return will be dual status tax return. Pension withdrawal will be reported as income.