I have gone through your query, as you noticed a lump on side of neck and you have cold
also but you didn't given complete information about lump as- for how long you have noticed it, weather is it painful or not, are you having fever
or feeling weakness, is the size of lump increasing or not, are you feeling any change in your appetite etc. Therefore I am considering as you are not having any of these associated symptoms.
To confirm the nature of lump you are advice to undergo F.N.A.C. testing from neck lump which will disclose the disease that can be plan for treatment. This test will not harm your pregnancy
I hope now you got the information about your query, if still any thing is not clear you may contact again.