Even the nicest surgeons seem to downplay the problems post-surgery with lymph nodes - I suppose they figure that they've got to go (the nodes, that is). For me, the underarm area was agony for a week or so after surgery - I felt as if it was blistering from contact with anything but the skin was actually fine. That settled down fairly quickly but 18 months later, it still gets slightly tender and burns a little. I also have an area where the drain was that remains tender and burns if I've been wearing a bra all day. I have never regained the feeling under my arm - it's still pretty numb. I get cording - no-one really knows why it occurs - some cording can be sorted but some like mine, can only be managed. My scar also likes to adhere to surrounding tissue. For these I have to do my stretches regularly and I see a specialist physio every 6-8 weeks to loosen things up. All of this adds up to a nuisance factor most of the time unless the cording flares badly which impacts on movement. I do what I can to stay on top of things. I can do most things except reach for the top shelf and I'm hyper-aware of injuries to the skin on that side which I find, bothers me most.
If you do decide to have the lymph nodes taken, please investigate getting a baseline measurement for fluid so that you can be monitored for lymphoedema in the future. A lymphoedema physio should be able to do this for you or your clinic or breast care nurse may have a recommendation.