This can often depend on who made your testosterone.
Brand name, or manufactured testosterone cyp such as Pfizer often use a thicker cottonseed oil (pharmacists call it a "dirty oil" compared to grape or sesame). In addition, there is a huge variation in preservative use in these injectables between manufacturers. Benzyl Alcohol is a common preservative that will cause irritation as described above. Most brand name and many compounded cypionates simply contain too much BA.
I personally use a compounded test cyp from both Empower and APS pharmacy using grapeseed oil and low percentage of BA. Never had a negative response since using them.
A reaction like this can also occur for other reasons, such as passing through vasculature during injection which causes swelling/lumps that will reside. Also, mixing testosterone with other compounds that have a different ph or preservative ratio can cause this as well.
Do not put ice on it as that will slow the healing process and metabolism of the medication from the injection site. Use heat and massage.