What are the odds of pregnancy post tubal ligation 4.5yrs ago? Anything to do besides surgery to increase these odds? I'm in good health and am 27yo.

Yes. Unlikely you would get pregnant without significant assisted reproduction. These days, it is probably more successful and less invasive and maybe less expensive to go through ivf rather than tubal reconnection. You definitely need a consult with a fertility specialist (reproductive endocrinologist).