Little concerned

I was diagnosed with large B cell lymphoma last July and started R-CHOP treatment soon after. I responded really well and my last chemo treatment was on December 31st. I did a maintenance round of Rituximab 3 weeks later and have another infusion tomorrow. My concern is that for past two weeks my hip has been bothering me and last week my neck started feeling sore and tight on the right side in the back of my neck. I've never experienced this so its making me worried that something is wrong. I don't have any other symptoms and don't feel any swelling in my neck or hip. Has anyone else ever experienced this?