The neurotransmitter in the periphery that is involved with
inhibitory actions on nerve firing... is called GABA.

You can buy a supplement, called PharmaGABA which will work a bit on your pain. It is sold on Amazon.

http://www.amazon.com/Nutrigold-Phar...rds=pharmaGABA

I use this at times and it is very helpful for stress, no side effects.

When you are pregnant cortisol levels go way up. This suppresses and latent autoimmune things you might have.
Also this protects the mother from autoimmune reactions to the fetus. Other hormones rise tremendously too. When you deliver, the cortisol falls quickly within the first week along with the other female hormones. Also at delivery there are many more endorphins present to block pain perception. After the baby comes there is a let down,and it can be swift and uncomfortable. This is when women may get their first autoimmune attack... rheumatoid arthritis, and lupus will flare at this time.

The drastically falling cortisol, will leave the mother vulnerable to stress for a while. Then it should return to normal with time.

New mothers can be very low in essential fatty acids because the baby took the mother's. So taking fish oil and flax oil may help.
B12 can be low, and also Vit D.

So many adjustments are going on in your body, and this viral thing and "colds" can be avoided if your Vit D is at a good level.
I suspect it is not, in your case.

You can try the PharmaGaba, 100mg twice a day. I take 200 mg at bedtime, and it has helped me thru some family emergencies here this past year. It also seems to make my pain levels less.
I've started my husband this past week on 100mg at bedtime and he is sleeping better, and less anxious about this summer's long trip and long vacation. This is not a cure, but it helps.