16 weeks pregnant w/pains in lower tummy / groin area

Im sixteen weeks and 1 days pregnant. I have felt flutters, very rare, infact only about once this week and a few during week 14. This is my 2nd pregnancy. (altho I have had a first trimester miscarriage before) Anyway I have had like back ache and some pains in my lower tummy/groin area since 3 nights ago. I cant decide if they are mestrual like pains or not but it is concerning me slighty. I did have backache earlier on in pregnancy and cramps but they went for a few weeks and now seem to have come back! Its not as if im dying with pain but its just enough to bother me. I have had no bleeding (thank god) so far and am still being sick! Midwife told me some people are unlucky enough to suffer with sickness throughout the whole pregnancy- i think i am one of those. Anyway just wanted to know what you think about these pains, should i be worried?