I began receiving social security at age 65. However, I also receive a small Cal State Teachers Retirement benefit. Social security leveled the " windfall tax" penalty against me and lessened my SS benefit by about $300 - $350 per month (The CALSTRS benefit is relatively small because I did not teach " full time" throughout my career ). Is there a way to bring Social Security to remove the " windfall tax " penalty in my case?

Erik,
You can reduce or eliminate the effect of the Windfall Elimination Provision (WEP) by working and earning 20 or more years of substantial earnings under Social Security, see: https://www.ssa.gov/pubs/EN-05-10045.pdf. The WEP was implemented in 1983 to eliminate an unintended windfall for people who didn't pay Social Security taxes for their whole career, i.e. getting a higher replacement rate than those who did pay Social Security taxes over their entire career.
Basically, the WEP ensures that people in both case are treated the same.
Best,
Mike