 [ Symptoms ] sharp back neck and arm pain on the left side this began suddenly about 12 hours ago the pain worsens with movement such as using my left arm turning my head to the left or lifting my head in general the main spot of pain feels like it is near my spine just under my left shoulderblade if i sneeze the pain shoots up and down on my spine and out to my left arm occasionally leaving a numbness in my left hand i am not an active person i primarilly work at my computer every day [ Disease ] there are a variety of possible explanations for sudden onset spotting on depoprovera 1 new infection with chlamydia  this is less likely unless you have a new sexual partner or a partner with multiple other partners 2 stress  many women using hormonal birth control pillspatchesringshot have had an apparent correlation between life stress and spotting on their birth control method i have also seen this occur in a couple of my postmenopausal patients yet there are no good studies in the medical literature on this phenomenon if there is a connection between life stress and the adrenal gland hormones that can be converted to weak estrogens that might be a trigger for breakthrough bleeding 3 normal effects of the depoprovera shot on the lining of the uterus  simply stated if the uterine lining is like grass or lawn estrogen is like the fertilizer causes a thickening of the lining and progesterone is like the lawnmower keeps the lining thin by three different mechanisms this is why depoprovera high dose synthetic progesterone brings about a thin lining and why birth control pills relatively progesterone dominant bring about shorter lighter periods if the lining of the uterus gets very thin it can prompt more breakthrough bleeding since it has been a month of constant spotting i would urge you to return to the gyn or clinic who administers your depoprovera they can check for infections if needed and can give you a more for sure answer about the spotting if someone is having very heavy breakthrough bleeding a short course of low dose estrogen pills can sometimes terminate the spotting 