Pain inner right thigh (groin area) down to foot. been weeks now. two negative ddimers but no ultrasound. no other symptoms. ultrasound worth it?

Not likely: If D-dimer is negative, you are very unlikely to have venous thrombi and ultrasound is not warranted. Beyond that one would need to examine you to ascertain the cause of pain. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex. Get HPV vaccine