FWIW,
Just started 600mg (3 x 200mg) per week with SoCos TE400 (3/19 batch date)… Same as you mentioned… First 2 injections left quad were no problem at all. the third, in the right quad, reacted much as you described. 4th in the left quad, and again… SUPER painful for a day or 2 afterwards. Got nervous, stared searching the forums thinking there is something wrong with the product, me, technique, etc…
What i did is… used a heating pad on the sore muscles to help break down the crystallization that takes place at higher concentrations of test. Immediate relief, also, stretching the muscles, while painful to do, helped tremendously. Now, prior to pinning, i warm the test in a candle warmer used for butter
Finally, now that i am into week 4, almost zero pip day after or following. Virgin muscles, high concentration test, was my problem… SoCos products appear to be g2g… Bloods in 2 weeks, will know then the efficacy but i suspect good outcomes based on the scale and clothes fitting.