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You can get a copy of your medical bills by calling your hospital or insurance provider, the statement that you will get should be good enough for the IRS.
For your business expenses if you have or had a separate bank account for your business you can request a copy of your bank statements, I know you won't be able to show the IRS all your expenses but at least they will be able to deduct some of the expenses.
If you filed your taxes with a professional tax preparer he/she should have copies of your tax return
If you can't find a copy of your tax returns you can go ahead and try to file your taxes and claim all your deductions, the calculation that the IRS gave you may not have all your exemptions and/or deductions.
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