Why a swollen lymph node that I have had for two years, has shrunk on taking Prednisone?

Hello doctor,

Two years ago, I discovered a small lump in my neck near the back right side. My GP said it did not seem like anything to worry about and to come back if it grows. I noticed no growth, but it did not go away or shrink either. A year and a half later, I developed a rash and stomach bloating and cramping, so I went to another doctor and said I was concerned the lump is lymphoma and causing the other symptoms. The doctor ordered an ultrasound. The node measured 0.39 x 0.35 x 0.15 inches. The results said it has the appearance of a lymph node. The doctor said I could have an ENT look at it if I like, but that he thinks it is nothing to worry about. The rash and stomach pains cleared up soon after, so I did not pursue it further.

Now, last month I started to have chest tightness where my air passage felt like it was being restricted. I went to an urgent care and was put on Prednisone for ten days. The chest tightness has cleared up, but there is still a little irritation in my right lung area like I can feel something in my chest. The strangest thing is that after two days on Prednisone, I could no longer feel the lump in my neck. In two years, it had not changed, and after two days of Prednisone, I could not feel it. However, within 3 to 4 days after stopping the Prednisone, I could start to feel it coming back. It is now about two weeks since I have stopped the Prednisone and I can easily feel the lump now. It does not feel as large as before yet and would be hard for someone else to feel, but it has returned after stopping the Prednisone. I did some reading about how Prednisone can mask lymphoma symptoms, such as temporarily shrinking the nodes. Are there any other explanations for why a swollen lymph node that I have had for two years, would shrink while on Prednisone and then start to regrow after stopping it?