Refunds are based on having more tax withheld from your paychecks than your tax liability, and on refundable credits that you might be eligible for. You have not mentioned any credits that you could be missing out on, like child tax credit. If you end up not owing anything, but not getting a refund, that means you did things "just right" and did not give the government an interest free loan all year.
But if you want the employer(s) to withhold more tax so that you get a refund, change your W-4.
https://turbotax.intuit.com/tax-tools/calculators/w4/
https://www.irs.gov/individuals/tax-withholding-estimator
https://www.irs.gov/pub/irs-pdf/fw4.pdf
No, you are not. it would seem your withholding taxes closely match your tax liability which is what is to be expected if you prepared your w-4 properly. you could file a new W-4 asking for additional taxes to be withheld. However, what you are fact doing is making an interest-free loan to the US Government until you get your refund. .