Could I be pregnant at 40 years old and had my tubal ligation done 10 years ago because I have lower abdiomal and back pain? Dizziness, going to bathroom more regular, sleep alot, can't get comfortable at night time, feel full, my breat are big and heavy.

Maybe. Clamps, probably hulka or filshie clips are the easiest to reverse and should give you the highest success rates. Even at 40, you should have good odds. Just make sure that you find a fertility specialist that has a lot of experience and expertise in microsurgical tubal reversals, your partner has a normal sperm count, you have a normal fsh and amh level and noting else obvious is wrong.
Possibly. . Possibly. Fertility rates are low at age 40 and failure of tubal ligation rates are quite low. However, if you were to become pregnant after a tubal ligation, that increases the chance of an ectopic pregnancy. An ectopic pregnancy can cause a woman to hemmorrhage. I do not know if you are pregnant or not. Recommend that you take a pregnancy test and call your doctor. If you start to bleed more, you need to go to the emergency room.
Could . Could you be pregnant after a btl 10 years ago at age 40, when you have a number of symptoms associated with pregnancy? Yes, but very unlikely. Btl surgery is very effective with failure rates <1% per year. Given that the surgery was effective for 10 years, that you are 40 and much less fertile now than when you had the surgery, it would be very unlikely that you are pregnant. The symptoms you have could be due to many other causes than pregnancy. Fortunately, pregnancy tests are very accurate if you are at least 12-14 days after ovulation. Blood tests are more accurate than home tests. I suggest that you do a home test or see your doctor for a blood test and then if not pregnant, get an evaluation by your primary care physician or gynecologist. Best wishes.