Hi, it's all about the odds at this point. The first thing to suspect would be some infection. That's especially so if the node enlarged rather quickly and then plateaued.
A lymphoma wouldn't aggressively grow, then just stop growing on its own. Even if the immune system suddenly kicked in and started destroying the cancer cells, the immune system wouldn't just stop doing that on it own. But a node that is reacting to an infection does plateau in size.
On the other hand, the factors that would tend to being cancer (besides continuous growth) would be if the node were rounded, instead of being long and thin. But the shape could be difficult to determine without a scan, such as a sonogram. A very large node would also be a bad sign.
As you seem to know, a painful node is usually reactive and so is not-cancer. It's even possible for the reacting to be from a medication, or an allergy, or be some autoimmunity.