Hi Jen: That's terrible your mom is having all these problems. Unfortunately, the flu-like sypmtoms usually last several days for most, but usual subside after that.
Has your mom ever had a back injury? I know that drawing my knees towards my chest helps with back pain, but I've had 7 back surgeries to explain this.
I would go with her to the Dr, if you can, and if she wants you too, and ask about any possible back injury. Bone and joint pain are also side effects of Reclast, but most find that it goes away soon. Which leads me to believe that something else might be going on to cause this pain, but only your Dr can figure this out.
Generally the iv osteo meds are much easier on your stomach, so if her stomach problems aren't resolving, then she should ask what she might be able to take to help this situation.
Also ask about any correlation between Reclast and the heart problems. Originally the FDA put out a warining on atrial fibrillation in conjunction to Reclast and other bisphosphonates, but since retracted that statement saying they couldn't find a true correlation between the two, a-fib and Reclast, and that they didn't recommend Drs stopping the iv since the risk of fracture was much higher than the group with heart problems. Also, some in the study had previous existin heart problems before the IV, so it was hard to determine if it was a result of their current heart probs or the IV med.
Keep an eye on all this, since the infusion is done and you are stuck, so to speak with whatever side effects she may have. Hopefully her problems will go away as it has for others, but if it doesn't make sure her Dr knows this and figures out a treatment for it.
If you want to read about Reclast IV, here's a link from The New England Journal of Medicine that lists all the side effects and many other concerns, it's also easy to understand and worth reading.
I wish you both the best and hope these problems go away, as it has for many others. That's not to say these things don't happen, because they do in some, it's just impossible to know if you will have these particular reactions since we are all so very different, with reactions.