Is spd something I need to be concerned about?
Not really hun, it's a pregnancy thing - although it does tend to get worse and be fairly painful. Apparently a hormone we produce at around 10-12 weeks weakens the cartilage like bit at the front of the pelvis (preparing for birth), and the added weight of baby puts pressure on the pelvis.
If it gets worse, you're best seeing your GP who can refer to the the physio.
The physio I saw today said that for most women it goes 24 to 48 hours after baby arrives.