Well I hate to tell you that is how my neck/back issues started, now I am looking at surgery in two weeks to replace 3 disks in my neck and being layed up for some time, the ONLY thing that seems to help (besides pain medicine) is a warm (not hot) heating pad, ice only made things worse, also I know from arm pain/numbness and loss of strength that usually surgery is the only option because this condition only gets worse, my level of pain/numbness in the last few weeks has tripled, have you tried talking to your ob/gyn? I know some medications are safe during pregnancy, but I feel for you, if it wasn't for prescription pain medicine and valume, I would fall apart, the pain is excruciating.... I can't even wash my own hair anymore.. hopefully yours isn't degenerative like mine... I wish you all the luck and I sympathize being pregnant twice myself, you don't need any added aches/pains!
I can't really say whether on not you should go to ER, because I don't know how bad you feel. Use your own judgment, if you think you should go, go.
If you decide not to go, you definitely need to see a Doctor, try to see one tomorrow if you can. And yes, you should be concerned.
Take Care
I would call my GP and ask the nurse what would be the best route for you to take.