Hello and welcome to the forum. That's unfortunate you have to wait 5 months. No way to work around that and receive care sooner? Angiomyolipomas are benign or non cancerous tumors. This is a quote from an article on these tumors. "Angiomyolipoma can be treated by the drug everolimus (Afinitor) that works by blocking the human target of rapamycin (mTOR) protein to affect many processes involved in cell growth. Researchers suggest that even if asymptomatic, angiomyolipoma that grows to 3 cm or more in diameter should be treated. Another treatment is embolization (technique in which the blood vessels in an angiomyolipoma tumor are sealed off); this technique can be preventative and is suggested to be used in angiomyolipomas 4 cm in diameter or larger to reduce the risk of hemorrhage (vessel rupture). Patients with angiomyolipoma tumors that are small and asymptomatic should be routinely seen with follow-up visits and measurements of the angiomyolipoma tumor size as some may quickly develop a growth rate of up to about 4 cm per year." https://www.medicinenet.com/angiomyolipoma/article.htm At the point the tumor was beyond 4 cm, treatment could have begun. I'd speak to your doctor about that. At 25 cm, it's now very large.
I'm sorry you are having tailbone pain. https://www.medicinenet.com/coccydynia/article.htm These are causes of that but with all of the kidney, surgical issues you've had along with this very large tumor, I would think it is plausible that it is all involved. Again, I would try to see if you can receive care sooner.
Angiomyolipomas are common benign renal neoplasms composed of vascular, smooth muscle, and fat components. These are often asymptomatic incidental imaging findings, although may be symptomatic when larger, typically when greater than 4 cm, at which point intervention may be considered due to risk of hemorrhage. Most are sporadic (80%); the remaining are seen in association with phakomatoses, the vast majority in the setting of tuberous sclerosis, although they have also been described in the setting of von Hippel-Lindau syndrome (VHL) and neurofibromatosis type 1 (NF1). In these cases, they present earlier (usually identified by age 10), are larger, and are more numerous. In all likelihood, your tailbone pain is probably not related to your angiomyolipoma. If your symptoms persist, consider MRI sacrum/coccyx.