Plus one on this...I always use 25 ga pins and in my quads i use 3cc syringe and my shoulders I use 1cc/25 ga...the difference in resistance is night and day..if this deosnt help, you can try heating the oil and also going to a bit larger pin if its still too hard.You are using a 3cc syringe, correct?
Try a 1cc syringe, and it will push with very little resistance.
You an LS1 fan Matt? Good choice. I know a guy who injected his biceps with 18g needle. Man did that leave a bruise!!