I have a question about reporting taxes withheld from my social security check. At present, I have 10% deducted for federal tax. Do I need to attach SSA-1099 to form 1040 like I do with 1099-R? They only send one copy and it says not to return it to ssa or the irs. Maybe I should attach a photocopy?
You do not need to attach the form SSA-1099 to your tax return. The instructions to the IRS form 1040 line 25(b) (which is where you need to put the value from box 6) explicitly mention form SSA-1099, but also explicitly only instruct to attach copies of form 1099-R.
Also, you can get additional copies of your form SSA-1099 if needed, follow the instructions here.
The reason is that SSA-1099 is issued by the Federal government and the IRS doesn't need to match what they report to you to what they report to them. They trust the SSA and if your return doesn't match what the SSA said they withheld - they'll come back to you asking questions.
For 1099-R - they need to verify that what you say matches to what the IRA/401(k) custodian reported, and then if you show the 1099-R but the custodian reported to the IRS something different - it's not you they'd be coming after.