Hello dear and welcome to the medhelp forum. There are certain complications possible with axillary lymph node dissection. Pain could be a direct consequence of tissue dissection; elbow pain could be due to compression of the supplying nerve due to local edema or swelling. All the nerves supplying the arm, axilla, forearm, elbow and hand traverse through the axilla in thick cords known as the brachial plexus before they supply their respective regions. Compressive injury due to swelling or direct injury to the nerve during surgery could be causing the pain in elbow. Nerve damage will also cause numbness, tingling, loss of motor function, and could be temporary or permanent. Try applying cold packs to the axilla to decrease swelling and its effects. Anti inflammatories could be prescribed. Consult your surgeon if it does not resolve in a few days. Best wishes and take care.
Well, obviously, don't straighten your arm out for a while longer. Aside from any nerve damage, swelling can be rather bad with any underarm surgery for some reason, and so that might be pushing on some nerves that go into your arm and ending at the elbow. Try some cold packs on your armpit, perhaps, just to see if reducing swelling there gives you a little relief. There's also a chance that when they did the surgery, your arm may have been in a strange position for the length of time they worked on you, and this has caused a sort of kink thing to happen to your arm.
Also, I had breast surgery, and my shoulder blade, of all things, hurt like mad for the longest time. Also, try to keep your arm propped up on a pillow when you're resting around the house, so it's higher than your heart. This would help if you perhaps had a temporary interruption in lymph flow, there's a bunch of those glands in the armpit. Hold your arm up, and with mild pressure kind of stroke the arm and then armpit skin towards the chest, and then across the chest to the center, then downward. Just do it for a few days, no more.
But could be a nerve was moved around or even nicked, altho surgeons do a very good job of avoiding those, as well as blood vessels and muscles in there, but anyway, some sort of nerve could be bothering you. It's been two weeks, so give it another week of applying cold and gently stroking arm skin towards the body. Also, you gradually want to increase movement in that arm, but nothing sudden, or you'll yank a muscle and THAT will hurt. If another week goes by and nothing changes and this is a pretty substantial bother, you may want to see your doc about it, he may be familiar with what it means when something in the arm gets to hurting.