Lymphoma starting in groin?

About 12 weeks ago I noticed a lump in my left groin, it was rubbery and not very mobile. I went to the doctors who seemed concerned and told me to come back in 3 weeks if it had not gone. Unfortunately it didn't go so I went back and saw a different doctor, he measured the lump as 1.5/2cm in size and told me not worry as I am young (I have just turned 23). About 4 weeks ago I then noticed more lumps on my left groin, and multiple in my neck. Another trip to the doctors and this time he booked me in for an ultrasound as he was concerned, the older lumps now felt more firm and fixed. However this was over 3 weeks ago and I still haven't heard back for my ultrasound date and now more large lumps have popped up on the right side of my groin this time. I've had blood work done 3 times over the last 12 weeks and all was fine. I have very itchy skin and extreme lower back pain also. 

How long have people waited for an ultrasound? And how soon after would they do a biopsy?

Can lymphoma still be an option of blood work is fine? 

Can lymphnodes just swell for no reason? 

 

Any advice would be great, I live alone with my 1 year old son and I am going out of my mind with worry.