Retirement tax questions

 Can I go back and file for the last 5 yrs?

Do you have adequate records of all that cash income an related expenses?  It is too late to file now for a Federal refund for any tax years prior to 2014. Only 2017 can be done online and efiled. For the others, see:

https://turbotax.intuit.com/personal-taxes/past-years-products/