Haven't taken it, but I distinctly remember the ad saying you had to be able to 'sit or stand for at least 30 minutes.' Apparently stomach pain and similar symptoms are a common side effect; in some cases they may be severe enough to prevent taking the drug. See your doctor for more information.
Boniva and Fosamax are the same class of drugs, with similar side effects; nonetheless, some people have reported less adverse effects with one or another drugs of this class. Again, consult with your doctor.