24mm+ stones in both kidneys. Can they cause pain in both flanks and in abdominal area when still in kidneys? Also passed 20 stones in 4 days.

Here are some... Analyzing the onset, duration, interval, degree, evolution, & resolution of pain and the sequence of events + the findings of timely physical exam will usually comes to a reliable conclusion of if the pain results from renal stones. Clinically, you are luckily able to pass so many in 4 days, but if really from kidneys or bladder. Managing renal stones can be staged as present and future care.
Yes. Yes, Jason, stones can cause all of those symptoms. You have a serious problem with this size and number of stones. You should investigate why you are having them get them removed, and get help starting a treatment plan to stop or slow down your stone formation. This many stones can cause kidney damage in the long run as well as serious infection. Find a urologist with an interest in stone disease.